.azurepipelines: Updated python version

Updated .azurepipelines to use newest python version

Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>

Signed-off-by: Kenneth Lautner <kenlautner3@gmail.com>
Reviewed-by: Sean Brogan <sean.brogan@microsoft.com>

.azurepipelines/Ubuntu-PatchCheck.yml

@@ -27,7 +27,7 @@ steps:
 
 - task: UsePythonVersion@0
   inputs:
-    versionSpec: '3.7.x'
+    versionSpec: '3.9.x'
     architecture: 'x64'
 
 - script: |

.azurepipelines/templates/platform-build-run-steps.yml

@@ -42,7 +42,7 @@ steps:
 
 - task: UsePythonVersion@0
   inputs:
-    versionSpec: "3.8.x"
+    versionSpec: "3.9.x"
     architecture: "x64"
 
 - script: pip install -r pip-requirements.txt --upgrade

.azurepipelines/templates/pr-gate-steps.yml

@@ -20,7 +20,7 @@ steps:
 
 - task: UsePythonVersion@0
   inputs:
-    versionSpec: '3.8.x'
+    versionSpec: '3.9.x'
     architecture: 'x64'
 
 - script: pip install -r pip-requirements.txt --upgrade