docs: Update bug report URLs for the gitlab migration

Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>

docs/bugs.html

@@ -24,8 +24,8 @@ The old bug database on SourceForge is no longer used.
 
 <p>
 To file a Mesa bug, go to
-<a href="https://bugs.freedesktop.org/enter_bug.cgi?product=Mesa">
-Bugzilla on freedesktop.org</a>
+<a href="https://gitlab.freedesktop.org/mesa/mesa/issues">
+GitLab on freedesktop.org</a>
 </p>
 
 <p>

docs/helpwanted.html

@@ -29,7 +29,7 @@ immediately checked into git because not enough people are testing them.
 Just applying patches, testing and reporting back is helpful.
 <li>
 <b>Driver debugging.</b>
-There are plenty of open bugs in the <a href="https://bugs.freedesktop.org/describecomponents.cgi?product=Mesa">bug database</a>.
+There are plenty of open bugs in the <a href="https://gitlab.freedesktop.org/mesa/mesa/issues">bug database</a>.
 <li>
 <b>Remove aliasing warnings.</b>
 Enable gcc's <code>-Wstrict-aliasing=2 -fstrict-aliasing</code> arguments, and

docs/releasing.html

@@ -285,7 +285,7 @@ To setup the branchpoint:
 
 <p>
 Now go to
-<a href="https://bugs.freedesktop.org/editversions.cgi?action=add&amp;product=Mesa" target="_parent">Bugzilla</a> and add the new Mesa version X.Y.
+<a href="https://gitlab.freedesktop.org/mesa/mesa/-/milestones" target="_parent">gitlab</a> and add the new Mesa version X.Y.
 </p>
 
 <p>