bump versions in github actions

Author: gabrielfalcao

.github/workflows/main.yml

@@ -41,75 +41,75 @@ jobs:
     runs-on: ubuntu-latest
     name: pre-install default version
     steps:
-    - name: pyenv + python 3.7.3
+    - name: pyenv + python 3.7.15
       id: pyenv
       uses: "gabrielfalcao/pyenv-action@master"
       with:
-        default: 3.7.3
+        default: 3.7.15
 
-    - name: pyenv + python 3.7.3 cached
+    - name: pyenv + python 3.7.15 cached
       id: pyenv2
       uses: "gabrielfalcao/pyenv-action@master"
       with:
-        default: 3.7.3
+        default: 3.7.15
 
     - name: List python versions
       run: pyenv versions
 
     - name: Verify default installation
-      run: python --version | grep 3.7.3
+      run: python --version | grep 3.7.15
 
   integration_test_preinstall_versions:
     runs-on: ubuntu-latest
     name: pre-install multiple versions of python
     steps:
-    - name: pyenv + python 3.6.5 and 3.7.3
+    - name: pyenv + python 3.6.15 and 3.7.15
       id: pyenv
       uses: "gabrielfalcao/pyenv-action@master"
       with:
-        default: 3.7.3
+        default: 3.7.15
         command: |
           pip install -U pip
           pip install -U setuptools
 
-        versions: 3.6.5,
+        versions: 3.6.15,
 
     - name: List python versions
       run: pyenv versions
 
     - name: Verify default installation
       run: python --version
 
-    - name: Verify python 3.6.5 installation
-      run: pyenv local 3.6.5 && python --version | grep 3.6.5
+    - name: Verify python 3.6.15 installation
+      run: pyenv local 3.6.15 && python --version | grep 3.6.15
 
-    - name: Verify python 3.7.3 installation
-      run: pyenv local 3.7.3 && python --version | grep 3.7.3
+    - name: Verify python 3.7.15 installation
+      run: pyenv local 3.7.15 && python --version | grep 3.7.15
 
 
   integration_test_run_command_after_each_installation:
     runs-on: ubuntu-latest
     name: run command after installing each python version
     steps:
-    - name: Python 3.6.5 and 3.7.3 with latest pip
+    - name: Python 3.6.15 and 3.7.15 with latest pip
       id: pyenv
       uses: "gabrielfalcao/pyenv-action@master"
       with:
-        default: 3.7.3
+        default: 3.7.15
         command: |
           pip install -U pip
           pip install -U setuptools
 
-        versions: 3.6.5,
+        versions: 3.6.15,
 
     - name: List python versions
       run: pyenv versions
 
     - name: Verify default installation
       run: python --version
 
-    - name: Verify pip version on python 3.6.5 installation
-      run: pyenv local 3.6.5 && pip --version
+    - name: Verify pip version on python 3.6.15 installation
+      run: pyenv local 3.6.15 && pip --version
 
-    - name: Verify pip version on python 3.7.3 installation
-      run: pyenv local 3.7.3 && pip --version
+    - name: Verify pip version on python 3.7.15 installation
+      run: pyenv local 3.7.15 && pip --version