Pin grafana/plugin-validator to v0.6.2 before go1.18 incompatibilites were introduced

Signed-off-by: Dom Del Nano <[email protected]>

Author: ddelnano

.github/workflows/release.yml

@@ -108,7 +108,7 @@ jobs:
           echo "::set-output name=checksum::$(cat ./${{ steps.metadata.outputs.archive-checksum }} | cut -d' ' -f1)"
       - name: Lint plugin
         run: |
-          git clone https://github.com/grafana/plugin-validator
+          git clone --branch v0.6.2 --depth 1 https://github.com/grafana/plugin-validator
           pushd ./plugin-validator/pkg/cmd/plugincheck
           go install
           popd