Bump Fedora CI images to latest version

* Try bumping Coverity up now that we should be on a newer version
  of it (so hopefully it supports GCC versions with 2 digits in their
  number).
* Allow the metadata test to fail because of an upstream bug in the
  appdata validation program that thinks the description tag isn't
  translated even though it is.

.gitlab-ci.yml

@@ -4,7 +4,7 @@ stages:
   - report
 
 default:
-  image: registry.gitlab.com/kicad/kicad-ci/source_containers/master/fedora:33
+  image: registry.gitlab.com/kicad/kicad-ci/source_containers/master/fedora:34
 
 
 ##########################################################################

.gitlab/coverity.yml

@@ -39,7 +39,7 @@ Coverity:
   tags:
     - coverity
   stage: build
-  image: registry.gitlab.com/kicad/kicad-ci/source_containers/master/fedora:31
+  image: registry.gitlab.com/kicad/kicad-ci/source_containers/master/fedora:34
   only:
     refs:
       - schedules

.gitlab/linux-metadata-validate.yml

@@ -6,7 +6,10 @@ validate_linux_metadata:
   needs: []
   interruptible: false
   # This is the only CI image with the utilities needed for this test
-  image: registry.gitlab.com/kicad/kicad-ci/source_containers/master/fedora:33
+  image: registry.gitlab.com/kicad/kicad-ci/source_containers/master/fedora:34
+  # Due to bug https://github.com/hughsie/appstream-glib/issues/381, this doesn't think our description tag
+  # is localized even though it actually is.
+  allow_failure: true
   only:
     refs:
       - master