hotfix master-coverage workflow (#31)

Author: maciej-sz

.github/workflows/master-coverage.yml

@@ -47,7 +47,7 @@ jobs:
       - name: Extract coverage data
         run: |
           COVERAGE=$(php scripts/get-coverage.php var/coverage/clover-main.xml)
-          COVERAGE_INT=${DIFF%%.*}
+          COVERAGE_INT=${COVERAGE%%.*}
           
           if [ "COVERAGE_INT" -ge 90 ]; then
             COLOR="#3fb911"