CI: reduce test cases

- GH: Remove python 3.7 on github actions test.
- Azure: Only run on master and rel-* branch.

Signed-off-by: Hiroshi Miura <miurahr@linux.com>

.github/workflows/test-install-qt.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       matrix:
         os: [windows-latest, macOS-latest, ubuntu-latest]
-        py: [3.6, 3.7, 3.8]
+        py: [3.6, 3.8]
     steps:
       - uses: actions/checkout@v1
         with:

azure-pipelines.yml

@@ -1,3 +1,9 @@
+trigger:
+  branches:
+    include:
+    - master
+    - rel-*
+
 jobs:
 - job: MatricesGenerator
   displayName: Matrices Generator