ci: Align Helm dependency setup in release workflow (#20)

Adds missing Helm dependency setup steps (repo add, dependency build) to the release workflow, mirroring the CI workflow. This ensures that dependencies are correctly handled during linting and packaging in the release process.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

.github/workflows/release.yml

@@ -22,6 +22,15 @@ jobs:
         with:
           version: v3.10.0
 
+      - name: Add Helm repositories
+        run: |
+          helm repo add bjw-s https://bjw-s-labs.github.io/helm-charts/ --force-update
+          helm repo add prometheus-community https://prometheus-community.github.io/helm-charts --force-update
+          helm repo update
+
+      - name: Build Helm chart dependencies
+        run: helm dependency build ./charts/iperf3-monitor
+
       - name: Helm Lint
         run: helm lint ./charts/iperf3-monitor
 
@@ -86,6 +95,15 @@ jobs:
           sudo wget https://github.com/mikefarah/yq/releases/latest/download/yq_linux_amd64 -O /usr/bin/yq &&\
           sudo chmod +x /usr/bin/yq
 
+      - name: Add Helm repositories
+        run: |
+          helm repo add bjw-s https://bjw-s-labs.github.io/helm-charts/ --force-update
+          helm repo add prometheus-community https://prometheus-community.github.io/helm-charts --force-update
+          helm repo update
+
+      - name: Build Helm chart dependencies
+        run: helm dependency build ./charts/iperf3-monitor
+
       - name: Set Chart Version from Tag
         run: |
           VERSION=$(echo "${{ github.ref_name }}" | sed 's/^v//')