Fix build timestamp when displaying powsybl version

[antoinebhs]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem?

No

What kind of change does this PR introduce?

#2778 introduced a regression when displaying the Powsybl versions.

What is the current behavior?

For example, when running the network-store-server, it displays:

2024-02-27T15:17:48.777+01:00  INFO 522297 --- [           main] c.p.n.s.s.NetworkStoreStartupRunner      : Powsybl versions:
+-----------------------+-----------------------+------------+------------------------------------------+------------------------+
| Repository name       | Maven project version | Git branch | Git version                              | Build timestamp        |
+-----------------------+-----------------------+------------+------------------------------------------+------------------------+
| powsybl-network-store | 1.8.0                 | UNKNOWN    | b05b4893bc334768b5e8651578179672be872150 | +56050-12-11T11:59:15Z |
| powsybl-core          | 6.1.2                 | UNKNOWN    | 2c718501f831c24059fd54f15240544e0d7c045c | +56031-03-09T20:10:56Z |
+-----------------------+-----------------------+------------+------------------------------------------+------------------------+

with an incorrect build timestamp.

What is the new behavior (if this is a feature change)?
When changing the conversion expecting a timestamp in milliseconds as described in https://www.mojohaus.org/buildnumber-maven-plugin/create-timestamp-mojo.html#timestampFormat, the timestamp displays correctly:

2024-02-27T15:07:20.904+01:00  INFO 512615 --- [           main] c.p.n.s.s.NetworkStoreStartupRunner      : Powsybl versions:
+-----------------------+-----------------------+------------+------------------------------------------+--------------------------+
| Repository name       | Maven project version | Git branch | Git version                              | Build timestamp          |
+-----------------------+-----------------------+------------+------------------------------------------+--------------------------+
| powsybl-network-store | 1.8.0                 | UNKNOWN    | b05b4893bc334768b5e8651578179672be872150 | 2024-01-30T15:49:40.755Z |
| powsybl-core          | 6.3.0-SNAPSHOT        | main       | 88eaca4bef31e5a334ffa27c6c5b68c4ff511d3d | 2024-02-27T14:00:00.212Z |
+-----------------------+-----------------------+------------+------------------------------------------+--------------------------+

Does this PR introduce a breaking change or deprecate an API?

• Yes
• No

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud