Bitbucket: Fix tag match

[samford]

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In some cases, the Bitbucket strategy currently matches versions from tag tarball links on a project's downloads/?tab=tags page. It appears that Bitbucket now uses a hash as the filename on this page instead of the tag name, so the existing regex no longer matches.

This adds an alternative regex to match versions from the tag name element (e.g., <td class="name">example-1.2.3</td>), which will fix version matching in this scenario.

Affected formulae are mvnvm, uru, when, and x265. All but uru are currently falling back to checking the Git tags from their head URL. With this change, the uru check works again and the others return to using the Bitbucket strategy (since it returns a version).

For what it's worth, now that Bitbucket has dropped Mercurial support, it should be technically possible to have Bitbucket use the Git strategy internally to check tags in this scenario. That may be preferable but I wanted to merge a fix in the interim time.

[MikeMcQuaid]

Thanks @samford!