Bring back PHP 8.1 builds

Since we still technically support this in PM, we need to test it, and it seems not that difficult to do support for.
I think we only dropped support because it was annoying to maintain so many branches, but with the new repo architecture that's no longer a problem.

Author: dktapps

.github/workflows/main.yml

@@ -17,6 +17,8 @@ jobs:
     strategy:
       matrix:
         include:
+          - pm-version-major: 5
+            php-version-base: "8.1"
           - pm-version-major: 5
             php-version-base: "8.2"
             special-release: default-latest #default = best for PM5, latest = display as latest on GitHub 

compile.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-PHP_VERSIONS=("8.2.29" "8.3.25" "8.4.12")
+PHP_VERSIONS=("8.1.33" "8.2.29" "8.3.25" "8.4.12")
 
 #### NOTE: Tags with "v" prefixes behave weirdly in the GitHub API. They'll be stripped in some places but not others.
 #### Use commit hashes to avoid this.

windows-compile-vs.ps1

@@ -1,7 +1,7 @@
 $ErrorActionPreference="Stop"
 $ProgressPreference="SilentlyContinue"
 
-$PHP_VERSIONS=@("8.2.29", "8.3.25", "8.4.12")
+$PHP_VERSIONS=@("8.1.33", "8.2.29", "8.3.25", "8.4.12")
 
 $PHP_SDK_VER="2.3.0"
 $ARCH="x64"