[provider/s3] Use mdatagen, promote to alpha (#38227)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

Officially promotes the s3 provider to alpha and records this with
mdatagen.

Requires
#38226.

Unblocks
open-telemetry/opentelemetry-collector-releases#546.

---------

Co-authored-by: Antoine Toulme <antoine@toulme.name>

.chloggen/s3provider-mdatagen.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: confmap/provider/s3
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Promote to alpha stability
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [38227]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

confmap/provider/s3provider/README.md

@@ -1,12 +1,31 @@
+# S3 Confmap Provider
+
+<!-- status autogenerated section -->
+| Status        |           |
+| ------------- |-----------|
+| Stability     | [alpha]  |
+| Distributions | [contrib] |
+| Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Aprovider%2Fs3provider%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Aprovider%2Fs3provider) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Aprovider%2Fs3provider%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Aprovider%2Fs3provider) |
+| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@Aneurysm9](https://github.com/Aneurysm9) |
+
+[alpha]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-stability.md#alpha
+[contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib
+<!-- end autogenerated section -->
+
 ## Summary
+
 This package provides a `ConfigMapProvider` implementation for Amazon S3 (`s3provider`) that allows the Collector the ability to load configuration by fetching and reading config objects stored in Amazon S3.
+
 ## How it works
+
 - It will be called by `ConfigMapResolver` to load configuration for the Collector.
 - By giving a config URI starting with prefix `s3://`, this `s3provider` will be used to download config objects from the given S3 URIs, and then use the downloaded configuration during Collector initialization.
 
 Expected URI format:
+
 - s3://[BUCKET].s3.[REGION].amazonaws.com/[KEY]
 
 Prerequistes:
+
 - Need to setup access keys from IAM console (aws_access_key_id and aws_secret_access_key) with permission to access Amazon S3
 - For details, can take a look at https://aws.github.io/aws-sdk-go-v2/docs/configuring-sdk/

confmap/provider/s3provider/metadata.yaml

@@ -1,3 +1,9 @@
+type: s3
+
 status:
+  class: provider
+  stability:
+    alpha: [provider]
+  distributions: [contrib]
   codeowners:
-    active: [Aneurysm9]
+    active: [Aneurysm9]

confmap/provider/s3provider/provider.go

@@ -1,6 +1,8 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
+//go:generate mdatagen metadata.yaml
+
 package s3provider // import "github.com/open-telemetry/opentelemetry-collector-contrib/confmap/provider/s3provider"
 
 import (

reports/distributions/contrib.yaml

@@ -109,6 +109,8 @@ components:
         - sumologic
         - tail_sampling
         - transform
+    provider:
+        - s3
     receiver:
         - active_directory_ds
         - aerospike