Try quoting.

Author: notroj

.github/workflows/linux.yml

@@ -64,7 +64,7 @@ jobs:
     - name: Set environment variables
       run: |
         echo "${{ matrix.env }}" >> $GITHUB_ENV
-        echo "JOBID=`echo ${{ matrix.env }} ${{ matrix.config }} | base64`" >> $GITHUB_ENV
+        echo "JOBID=`echo '${{ matrix.env }} ${{ matrix.config }}' | base64`" >> $GITHUB_ENV
     - name: apt refresh
       run: sudo apt-get -o Acquire::Retries=5 update
     - name: Install prerequisites