removed pharo8

Author: noha

.github/workflows/build.yml

@@ -20,7 +20,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        smalltalk: [ Pharo64-11, Pharo64-10, Pharo64-9.0, Pharo64-8.0 ]
+        smalltalk: [ Pharo64-11, Pharo64-10, Pharo64-9.0 ]
     name: ${{ matrix.smalltalk }}
     steps:
       - uses: actions/checkout@v2