MediaWiki: Add PHP calendar extension

This has been needed for a while, but only noticed recently.

Refs:
* https://github.com/wikimedia/mediawiki-docker/pull/108
* https://github.com/wikimedia/mediawiki-docker/pull/109

library/mediawiki

@@ -2,7 +2,7 @@ Maintainers: David Barratt <[email protected]> (@davidbarratt),
              Kunal Mehta <[email protected]> (@legoktm),
              addshore <[email protected]> (@addshore)
 GitRepo: https://github.com/wikimedia/mediawiki-docker.git
-GitCommit: ce983a609daf0e23070931a55f892e3d7d0924a3
+GitCommit: bc248a718e85005b966c4f84ccebc92bdce58c4f
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, ppc64le
 
 Tags: 1.37.2, 1.37, stable, latest