chore:(deps): bump bootstrap from 4.5.1 to 4.5.2 in /explorer

Bumps [bootstrap](https://github.com/twbs/bootstrap) from 4.5.1 to 4.5.2.
- [Release notes](https://github.com/twbs/bootstrap/releases)
- [Commits](twbs/bootstrap@v4.5.1...v4.5.2)

Signed-off-by: dependabot[bot] <support@github.com>

explorer/package.json

@@ -19,7 +19,7 @@
     "@types/react-select": "^3.0.16",
     "@types/socket.io-client": "^1.4.33",
     "bn.js": "^5.1.2",
-    "bootstrap": "^4.5.1",
+    "bootstrap": "^4.5.2",
     "bs58": "^4.0.1",
     "chai": "^4.2.0",
     "humanize-duration-ts": "^2.1.1",