Systematically add `PIP_BREAK_SYSTEM_PACKAGES` to all .yml files from which pip is called. (#4705)

* Systematically add PIP_BREAK_SYSTEM_PACKAGES to all .yml files from which pip is called.

* Try gcc:10-bullseye (because gcc:10 is broken: https://github.com/docker-library/gcc/issues/95)

* bug fix (matrix did not work as hoped)

.github/workflows/ci.yml

@@ -16,6 +16,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
+  PIP_BREAK_SYSTEM_PACKAGES: 1
   PIP_ONLY_BINARY: numpy
   FORCE_COLOR: 3
   PYTEST_TIMEOUT: 300
@@ -455,16 +456,16 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { gcc: 7, std: 11 }
-          - { gcc: 7, std: 17 }
-          - { gcc: 8, std: 14 }
-          - { gcc: 8, std: 17 }
-          - { gcc: 10, std: 17 }
-          - { gcc: 11, std: 20 }
-          - { gcc: 12, std: 20 }
+          - { gcc: 7, std: 11, container_suffix: "" }
+          - { gcc: 7, std: 17, container_suffix: "" }
+          - { gcc: 8, std: 14, container_suffix: "" }
+          - { gcc: 8, std: 17, container_suffix: "" }
+          - { gcc: 10, std: 17, container_suffix: "-bullseye" }
+          - { gcc: 11, std: 20, container_suffix: "" }
+          - { gcc: 12, std: 20, container_suffix: "" }
 
     name: "🐍 3 • GCC ${{ matrix.gcc }} • C++${{ matrix.std }}• x64"
-    container: "gcc:${{ matrix.gcc }}"
+    container: "gcc:${{ matrix.gcc }}${{ matrix.container_suffix }}"
 
     steps:
     - uses: actions/checkout@v3

.github/workflows/configure.yml

@@ -13,6 +13,7 @@ permissions:
   contents: read
 
 env:
+  PIP_BREAK_SYSTEM_PACKAGES: 1
   # For cmake:
   VERBOSE: 1
 

.github/workflows/pip.yml

@@ -16,6 +16,7 @@ permissions:
   contents: read
 
 env:
+  PIP_BREAK_SYSTEM_PACKAGES: 1
   PIP_ONLY_BINARY: numpy
 
 jobs:

.github/workflows/upstream.yml

@@ -12,6 +12,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
+  PIP_BREAK_SYSTEM_PACKAGES: 1
   PIP_ONLY_BINARY: ":all:"
   # For cmake:
   VERBOSE: 1