ci: install a more recent meson in the ubuntu 20.04 image

.gitlab-ci.yml

@@ -55,7 +55,7 @@ include:
 .ubuntu:
   variables:
     # Update this tag when you want to trigger a rebuild
-    FDO_DISTRIBUTION_TAG: '2021-06-10.0'
+    FDO_DISTRIBUTION_TAG: '2021-06-18.0'
     FDO_DISTRIBUTION_VERSION: '20.04'
     FDO_DISTRIBUTION_PACKAGES: >-
       debhelper-compat
@@ -75,10 +75,13 @@ include:
       libva-dev
       libv4l-dev
       libx11-dev
-      meson
+      ninja-build
       pkg-config
       systemd
       xmltoman
+      python3-pip
+    FDO_DISTRIBUTION_EXEC: >-
+      pip3 install meson
 
 .coverity:
   variables: