CI-unixish.yml: removed macos-11 builds and no longer build with qmake on MacOS (#5614)

Removed all `macos-11` builds as `brew` no longer supports it and we use
it in most steps:
```
Warning: You are using macOS 11.
We (and Apple) do not provide support for this old version.
It is expected behaviour that some formulae will fail to build in this old version.
It is expected behaviour that Homebrew will be buggy and slow.
Do not create any issues about this on Homebrew's GitHub repositories.
Do not create any issues even if you think this message is unrelated.
Any opened issues will be immediately closed without response.
Do not ask for help from Homebrew or its maintainers on social media.
You may ask for help in Homebrew's discussions but are unlikely to receive a response.
Try to figure out the problem yourself and submit a fix as a pull request.
We will review it but may or may not accept it.
```

Also `brew` might no longer provide pre-built Qt5 packages which will
cause the step to run for hours as it will compile it on demand - see
https://github.com/danmar/cppcheck/actions/runs/6735637341/job/18314354679
for such an instance.

Author: firewave

.github/workflows/CI-unixish.yml

@@ -19,7 +19,7 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, macos-11, macos-12]
+        os: [ubuntu-20.04, ubuntu-22.04, macos-12]
         include:
           - use_qt6: On
           - os: ubuntu-20.04
@@ -81,7 +81,7 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, macos-11, macos-12]
+        os: [ubuntu-20.04, ubuntu-22.04, macos-12]
         include:
           - use_qt6: On
           - os: ubuntu-20.04
@@ -162,7 +162,7 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, macos-11, macos-12]
+        os: [ubuntu-20.04, ubuntu-22.04, macos-12]
       fail-fast: false # Prefer quick result
 
     runs-on: ${{ matrix.os }}
@@ -194,7 +194,7 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, macos-11, macos-12]
+        os: [ubuntu-20.04, ubuntu-22.04, macos-12]
       fail-fast: false # Prefer quick result
 
     runs-on: ${{ matrix.os }}
@@ -226,7 +226,7 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, macos-11, macos-12]
+        os: [ubuntu-20.04, ubuntu-22.04, macos-12]
       fail-fast: false # Prefer quick result
 
     runs-on: ${{ matrix.os }}
@@ -248,7 +248,8 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, macos-11, macos-12]
+        # no longer build with qmake on MacOS as brew might lack pre-built Qt5 packages causing the step to run for hours
+        os: [ubuntu-20.04, ubuntu-22.04]
       fail-fast: false # Prefer quick result
 
     runs-on: ${{ matrix.os }}
@@ -329,7 +330,7 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, macos-11, macos-12]
+        os: [ubuntu-20.04, ubuntu-22.04, macos-12]
       fail-fast: false # Prefer quick result
 
     runs-on: ${{ matrix.os }}