Require python3.9 to workaround some issues...

... with python3.7 on windows - specifically:
- pysqlite wheel doesn't build without patching at <3.8
- abi info on windows gets better at 3.9

.github/workflows/build.yml

@@ -33,7 +33,7 @@ jobs:
     env:
       CCACHE_DIR: ${{ github.workspace }}/.cache/ccache
       CCACHE_COMPRESS: "1"
-      PY_VER: "3.7"
+      PY_VER: "3.9"
       KART_POSTGRES_URL: "postgresql://postgres:@localhost:5432/postgres"
       KART_SQLSERVER_URL: "mssql://sa:PassWord1@localhost:1433/master"
       KART_MYSQL_URL: "mysql://root:PassWord1@localhost:3306"
@@ -271,7 +271,7 @@ jobs:
     name: Windows
     runs-on: windows-2019
     env:
-      PY_VER: "3.7"
+      PY_VER: "3.9"
       FORCE_COLOR: "YES"
 
     # We want to run on external PRs, but not on our own internal PRs as they'll be run
@@ -507,7 +507,7 @@ jobs:
     env:
       CCACHE_DIR: ${{ github.workspace }}/.cache/ccache
       CCACHE_COMPRESS: "1"
-      PY_VER: "3.7"
+      PY_VER: "3.9"
       HOMEBREW_CACHE: ${{ github.workspace }}/.cache/brew
       HOMEBREW_NO_INSTALL_CLEANUP: "1"
       FORCE_COLOR: "YES"
@@ -778,7 +778,7 @@ jobs:
     env:
       CCACHE_DIR: ${{ github.workspace }}/.cache/ccache
       CCACHE_COMPRESS: "1"
-      PY_VER: "3.7"
+      PY_VER: "3.9"
       KART_POSTGRES_URL: "postgresql://postgres:@localhost:5432/postgres"
       KART_SQLSERVER_URL: "mssql://sa:PassWord1@localhost:1433/master"
       KART_MYSQL_URL: "mysql://root:PassWord1@localhost:3306"
@@ -1032,7 +1032,7 @@ jobs:
     runs-on: windows-2019
     continue-on-error: true
     env:
-      PY_VER: "3.7" # needs to match the Windows job since we use its vendor archive.
+      PY_VER: "3.9" # needs to match the Windows job since we use its vendor archive.
       FORCE_COLOR: "YES"
 
     # We want to run on external PRs, but not on our own internal PRs as they'll be run

CMakeLists.txt

@@ -47,7 +47,7 @@ endif()
 
 # OSX: prefer Homebrew over Frameworks
 set(Python3_FIND_IMPLEMENTATIONS "CPython")
-find_package(Python3 3.7 REQUIRED COMPONENTS Development Interpreter)
+find_package(Python3 3.9 REQUIRED COMPONENTS Development Interpreter)
 pythongetabiinfo()
 
 if(USE_VCPKG)

vcpkg-vendor/CMakeLists.txt

@@ -40,7 +40,7 @@ set(EXE_LIST "")
 #
 # Need Development here or VcPkg falls back to the system interpreter
 find_package(
-  Python3 3.7
+  Python3 3.9
   COMPONENTS Development Interpreter
   REQUIRED)
 cmake_path(GET Python3_STDLIB FILENAME Python3_STDLIB_DIR_NAME)