fix(grpc instrumentation): skip JRuby tests since gRPC is not compatible with JRuby

reference grpc/grpc#6705

Author: michal-kazmierczak

.github/workflows/ci-instrumentation.yml

@@ -103,6 +103,7 @@ jobs:
           [[ "${{ matrix.gem }}" == "lmdb"                     ]] && echo "skip=true" >> $GITHUB_OUTPUT
           [[ "${{ matrix.gem }}" == "rack"                     ]] && echo "skip=true" >> $GITHUB_OUTPUT
           [[ "${{ matrix.gem }}" == "rails"                    ]] && echo "skip=true" >> $GITHUB_OUTPUT
+          [[ "${{ matrix.gem }}" == "grpc"                     ]] && echo "skip=true" >> $GITHUB_OUTPUT
           [[ "${{ matrix.gem }}" == "gruf"                     ]] && echo "skip=true" >> $GITHUB_OUTPUT
           # This is essentially a bash script getting evaluated, so we need to return true or the whole job fails.
           true