Upgraded pyenv github action.

Author: abingham

.github/workflows/actions.yml

@@ -27,7 +27,7 @@ jobs:
           sudo rm /usr/bin/conda
 
       - name: "Install pyenv"
-        uses: "gabrielfalcao/pyenv-action@v16"
+        uses: "gabrielfalcao/pyenv-action@v18"
 
       - name: "Configure pyenv-virtualenv"
         run: |
@@ -64,7 +64,7 @@ jobs:
           sudo rm /usr/bin/conda
 
       - name: "Install pyenv"
-        uses: "gabrielfalcao/pyenv-action@v16"
+        uses: "gabrielfalcao/pyenv-action@v18"
 
       - name: "Configure pyenv-virtualenv"
         run: |