Try only one api call?

Author: WardBrian

.github/workflows/main.yml

@@ -9,7 +9,20 @@ on:
       - '**'
   pull_request:
 jobs:
+  get-cmdstan-version:
+    name: version check
+    runs-on: ubuntu-latest
+    steps:
+      - name: Get CmdStan version
+        id: check-cmdstan
+        # get the latest cmdstan version to use as part of the cache key
+        run: |
+          echo "::set-output name=version::$(python -c 'import requests;print(requests.get("https://api.github.com/repos/stan-dev/cmdstan/releases/latest").json()["tag_name"][1:])')"
+    outputs:
+      version: ${{ steps.check-cmdstan.outputs.version }}
+
   cmdstanpy:
+    needs: get-cmdstan-version
     name: tests
     runs-on: ${{ matrix.os }}
     strategy:
@@ -57,18 +70,11 @@ jobs:
       - name: Show libraries
         run: python -m pip freeze
 
-      - name: Get CmdStan version
-        id: check-cmdstan
-        # get the latest cmdstan version to use as part of the cache key
-        run: |
-          echo "::set-output name=version::$(python -c 'import requests;print(requests.get("https://api.github.com/repos/stan-dev/cmdstan/releases/latest").json()["tag_name"][1:])')"
-        shell: bash
-
       - name: CmdStan installation cacheing
         uses: actions/cache@v2
         with:
           path: ~/.cmdstan
-          key: ${{ runner.os }}-cmdstan-${{ steps.check-cmdstan.outputs.version }}-${{ hashFiles('**/install_cmdstan.py') }}
+          key: ${{ runner.os }}-cmdstan-${{ needs.get-cmdstan-version.outputs.version }}-${{ hashFiles('**/install_cmdstan.py') }}
 
       - name: Install CmdStan (Linux, macOS)
         if: matrix.os != 'windows-latest'