Remove obsolote gcc8 workflow, update gh actions

Created by: tmadlener

BEGINRELEASENOTES

• Remove obsolete gcc8 based workflow and update github actions versions

ENDRELEASENOTES

.github/workflows/linux.yml

@@ -9,14 +9,11 @@ jobs:
       matrix:
         COMPILER: [gcc10, clang11]
         LCG: [100]
-        include:
-          - COMPILER: gcc8
-            LCG: 99python2
 
     steps:
-    - uses: actions/checkout@v2
-    - uses: cvmfs-contrib/github-action-cvmfs@v2
-    - uses: aidasoft/run-lcg-view@v3
+    - uses: actions/checkout@v3
+    - uses: cvmfs-contrib/github-action-cvmfs@v3
+    - uses: aidasoft/run-lcg-view@v4
       with:
         view-path: "/cvmfs/clicdp.cern.ch/iLCSoft/lcg/${{ matrix.LCG }}/nightly/x86_64-centos7-${{ matrix.COMPILER }}-opt"
         setup-script: "init_ilcsoft.sh"