Only fetch assets when not using the cache

- Run more steps conditionally based on whether there was a cache hit
- Fix the step name in one cases (`restore` needed to become `cache`)
- Always run the PATH step but don't add the same dir to the path twice

The last one should make the action idempotent.

actions/setup-argo/action.yaml

@@ -19,6 +19,7 @@ runs:
         key: argo-${{ runner.os }}-${{ runner.arch }}-${{ inputs.version }}
 
     - name: Normalize runner.os to match Argo release
+      if: steps.cache.outputs.cache-hit != 'true'
       shell: bash
       env:
         OS: ${{ runner.os }}
@@ -30,17 +31,17 @@ runs:
     # runner.arch options: X86, X64, ARM, or ARM64.
     # argo release: arm64, amd64, ppc64le, s390x.
     # If it ain't arm64 or amd64, it'll fall back to runner.arch.
-    - if: runner.arch == 'X64'
+    - if: runner.arch == 'X64' && steps.cache.outputs.cache-hit != 'true'
       shell: sh
       run: echo "ARCH=amd64" >> "$GITHUB_ENV"
 
-    - if: runner.arch == 'ARM64'
+    - if: runner.arch == 'ARM64' && steps.cache.outputs.cache-hit != 'true'
       shell: sh
       run: echo "ARCH=arm64" >> "$GITHUB_ENV"
 
     - name: Fetch Github Release Asset
       id: fetch_asset
-      if: steps.restore.outputs.cache-hit != 'true'
+      if: steps.cache.outputs.cache-hit != 'true'
       uses: dsaltares/fetch-gh-release-asset@a40c8b4a0471f9ab81bdf73a010f74cc51476ad4 # 1.1.1
       with:
         repo: "argoproj/argo-workflows"
@@ -59,4 +60,10 @@ runs:
     - name: Add binary to path
       shell: sh
       run: |
-        echo "${{ github.workspace }}/bin" >> $GITHUB_PATH
+        # Check if `argo` is already in the PATH
+        if command -v argo &> /dev/null; then
+          exit 0
+        fi
+
+        echo "Adding '${{ github.workspace }}/bin' to the PATH so the 'argo' binary can be found"
+        echo "${{ github.workspace }}/bin" >> "${GITHUB_PATH}"