ci: reduce no. of MacOS jobs (#4940)

This was increasing the wait times of the CI.

Also enabled codecov failure to not fail the whole CI pipeline.

.github/workflows/tests.yaml

@@ -37,13 +37,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-18.04, windows-2019, macos-10.15, macos-11.0]
+        os: [ubuntu-18.04, windows-2019, macos-10.15]
         pyv: ["3.6", "3.7", "3.8", "3.9"]
+        include:
+          - os: "macos-11.0"
+            pyv: "3.9"
         exclude:
-          - os: macos-11.0
-            pyv: "3.6"
-          - os: macos-11.0
-            pyv: "3.7"
+          - os: macos-10.15
+            pyv: "3.9"
+
     steps:
     - uses: actions/[email protected]
     - name: Set up Python
@@ -70,7 +72,7 @@ jobs:
       uses: codecov/[email protected]
       with:
         file: ./coverage.xml
-        fail_ci_if_error: true
+        fail_ci_if_error: false
     - name: Post TAP
       # Running custom fork with an option, that does not fail CI on error
       uses: skshetry/flaky-service/packages/action@master