build: Set precise runner versions

.github/workflows/build.yml

@@ -10,7 +10,7 @@ jobs:
 
   commitsar:
     name: Verify commit messages
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: Check out code
         uses: actions/checkout@v1
@@ -19,7 +19,7 @@ jobs:
 
   pre-commit:
     name: Generic pre-commit checks
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
         with:
@@ -37,7 +37,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-20.04, macos-11, windows-2019]
         draft: [draft201909, draft202012]
 
     name: Test ${{ matrix.draft }} (stable) on ${{ matrix.os}}
@@ -57,7 +57,7 @@ jobs:
 
   coverage:
     name: Run test coverage
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
         with:
@@ -82,7 +82,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-20.04, macos-11, windows-2019]
         python-version: ['3.6', '3.7', '3.8', '3.9']
 
     name: Python ${{ matrix.python-version }} on ${{ matrix.os }}
@@ -109,7 +109,7 @@ jobs:
         working-directory: ./bindings/python
 
   test-python-sdist:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     name: Testing Python source code distribution
     steps:
       - uses: actions/checkout@v2
@@ -138,7 +138,7 @@ jobs:
 
   fmt:
     name: Rustfmt
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
@@ -152,7 +152,7 @@ jobs:
 
   clippy:
     name: Clippy
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
         with:

.github/workflows/python-release.yml

@@ -10,13 +10,13 @@ jobs:
     name: Wheels for Python ${{ matrix.python-version }} / ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-latest, windows-latest]
+        os: [macos-11, windows-2019]
         python-version: ['3.6', '3.7', '3.8', '3.9']
         architecture: [x86, x64]
         exclude:
-        - os: macos-latest
+        - os: macos-11
           architecture: x86
-        - os: windows-latest
+        - os: windows-2019
           # TODO: Re-enable windows 32bits
           architecture: x86
     runs-on: ${{ matrix.os }}
@@ -49,7 +49,7 @@ jobs:
         # List of the language-implementation API pairs to publish wheels for
         # The list of supported is obtainable by running `docker run quay.io/pypa/manylinux2014_x86_64 ls /opt/python`
         PYTHON_IMPLEMENTATION_ABI: [cp36-cp36m, cp37-cp37m, cp38-cp38, cp39-cp39]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     container: quay.io/pypa/manylinux2014_x86_64  # Builds wheels on CentOS 7 (supported until 2024)
     env:
       # Variable needed for PyO3 to properly identify the python interpreter
@@ -96,7 +96,7 @@ jobs:
 
   create_source_dist:
     name: Create sdist package
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
@@ -123,7 +123,7 @@ jobs:
     - create_wheels_manylinux
     - create_source_dist
     name: Upload Artifacts to PyPi
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
     - uses: actions/download-artifact@v2
       with:

.github/workflows/rust-release.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   rust-release:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1