ci: pin helm version (#19860)

Author: TheRealNoob

.github/workflows/helm-ci.yml

@@ -36,9 +36,9 @@ jobs:
           persist-credentials: false
 
       - name: Set up Helm
-        uses: azure/setup-helm@b9e51907a09c216f16ebe8536097933489208112 # v4
+        uses: azure/setup-helm@1a275c3b69536ee54be43f2070a358922e12c8d4 # v4.3.1
         with:
-          version: v3.8.2
+          version: v3.18.6
 
       # Python is required because `ct lint` runs Yamale (https://github.com/23andMe/Yamale) and
       # yamllint (https://github.com/adrienverge/yamllint) which require Python
@@ -135,7 +135,9 @@ jobs:
           persist-credentials: 'false'
 
       - name: Set up Helm
-        uses: azure/setup-helm@b9e51907a09c216f16ebe8536097933489208112  # v4.3.0
+        uses: azure/setup-helm@1a275c3b69536ee54be43f2070a358922e12c8d4 # v4.3.1
+        with:
+          version: v3.18.6
 
       - name: Install Flux CLI
         uses: fluxcd/flux2/action@6bf37f6a560fd84982d67f853162e4b3c2235edb  # v2.6.4