downgrade meson in github actions

.github/workflows/abicheck.yml

@@ -4,7 +4,7 @@ env:
   build_options: -Dbuildtype=debug -Denable-true-color=yes -Dwith-proxy=yes -Dc_args=-DPERL_EUPXS_ALWAYS_EXPORT
   prefix: /usr/local
   apt_build_deps: ninja-build libutf8proc-dev libperl-dev libotr5-dev
-  get_pip_build_deps: pip3 install setuptools; pip3 install wheel; pip3 install meson
+  get_pip_build_deps: pip3 install setuptools; pip3 install wheel; pip3 install 'meson<0.58.0'
   getabidef_def: getabidef() { awk '$1=="#define" && $2=="IRSSI_ABI_VERSION" { print $3 }' "$1"/include/irssi/src/common.h; }
 jobs:
   build-base-ref:

.github/workflows/check.yml

@@ -34,16 +34,25 @@ jobs:
     env:
       CC: ${{ matrix.compiler }}
     needs: dist
+    continue-on-error: ${{ contains(matrix.flags, 'FAILURE-OK') }}
     strategy:
+      fail-fast: false
       matrix:
         os: [ubuntu-16.04, ubuntu-latest]
         builder: [meson, configure]
         compiler: [clang, gcc]
+        flags: [regular]
         include:
           - os: ubuntu-16.04
             builder: meson
             meson_ver: ==0.49.2
             setuptools_ver: <51
+          - os: ubuntu-latest
+            builder: meson
+            meson_ver: <0.58.0
+          - os: ubuntu-latest
+            builder: meson
+            flags: meson-latest FAILURE-OK
     steps:
       - name: fetch dist
         uses: actions/download-artifact@v2