[ci] Move all runners to ubuntu-latest

Also s/clang-8/clang-9/ due to clang-8 not being available as part of
https://apt.llvm.org/focal/dists/

Author: serge-sans-paille

.github/workflows/cmake.yml

@@ -8,7 +8,7 @@ defaults:
     shell: bash -l {0}
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
     - name: Checkout xsimd
       uses: actions/checkout@v3

.github/workflows/cross-rvv.yml

@@ -7,7 +7,7 @@ env:
   GCC_VERSION: "12"
 jobs:
   build:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-latest
     name: 'RISC-V RVV${{ matrix.vector_bits }}'
     strategy:
       matrix:

.github/workflows/cross-sve.yml

@@ -5,7 +5,7 @@ concurrency:
   cancel-in-progress: true
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     name: 'Arm SVE${{ matrix.vector_bits }}'
     strategy:
       matrix:

.github/workflows/emulated.yml

@@ -8,7 +8,7 @@ defaults:
     shell: bash -l {0}
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     name: '${{ matrix.sys.compiler }} ${{ matrix.sys.version }} - emulated'
     strategy:
       matrix:

.github/workflows/linux.yml

@@ -8,7 +8,7 @@ defaults:
     shell: bash -l {0}
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     name: '${{ matrix.sys.compiler }} ${{ matrix.sys.version }} - ${{ matrix.sys.flags }}'
     strategy:
       matrix:
@@ -23,7 +23,7 @@ jobs:
           - { compiler: 'gcc',   version: '11', flags: 'avx512vbmi' }
           - { compiler: 'gcc',   version: '11', flags: 'avx512vbmi2' }
           - { compiler: 'gcc',   version: '11', flags: 'avx512vnni' }
-          - { compiler: 'clang', version: '8',  flags: 'force_no_instr_set' }
+          - { compiler: 'clang', version: '9',  flags: 'force_no_instr_set' }
           - { compiler: 'clang', version: '10', flags: 'enable_xtl_complex' }
           - { compiler: 'clang', version: '12', flags: 'avx' }
           - { compiler: 'clang', version: '13', flags: 'sse3' }
@@ -54,11 +54,7 @@ jobs:
         LLVM_VERSION=${{ matrix.sys.version }}
         #sudo add-apt-repository ppa:ubuntu-toolchain-r/test || exit 1
         wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add - || exit 1
-        if [[ $LLVM_VERSION -ge 13 ]]; then
-          sudo add-apt-repository "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-$LLVM_VERSION main" || exit 1
-        else
-          sudo add-apt-repository "deb http://apt.llvm.org/focal/ llvm-toolchain-focal main" || exit 1
-        fi || exit 1
+        sudo add-apt-repository "deb http://apt.llvm.org/focal/ llvm-toolchain-focal-$LLVM_VERSION main" || exit 1
         sudo apt-get update || exit 1
         sudo apt-get --no-install-suggests --no-install-recommends install clang-$LLVM_VERSION || exit 1
         sudo apt-get --no-install-suggests --no-install-recommends install g++-9 g++-9-multilib || exit 1