ci: update ci configs

- add windows runner
- update actions versions
- other minor enhancements

scripts/ci/run

@@ -1,7 +1,8 @@
-#!/bin/bash -eu
+#!/bin/bash
+set -eu
 
 cd "$(dirname "$0")"
-cd ../..
+cd .. # git root
 
 if ! command -v sudo; then
     # CI or Docker sometimes doesn't have it, so useful to have a dummy
@@ -10,16 +11,31 @@ if ! command -v sudo; then
     }
 fi
 
-if ! [ -z "$CI" ]; then
+if [ -n "${CI-}" ]; then
     # install OS specific stuff here
-    if [[ "$OSTYPE" == "darwin"* ]]; then
+    case "$OSTYPE" in
+    darwin*)
         # macos
         brew install fd
-    else
+        ;;
+    cygwin* | msys* | win*)
+        # windows
+        :
+        ;;
+    *)
+        # must be linux?
         sudo apt update
         sudo apt install fd-find
-    fi
+        ;;
+    esac
 fi
 
-pip3 install --user tox
-tox
+
+PY_BIN="python3"
+# some systems might have python pointing to python3
+if ! command -v python3 &> /dev/null; then
+    PY_BIN="python"
+fi
+
+"$PY_BIN" -m pip install --user tox
+"$PY_BIN" -m tox