Use gem unpack to get precompiled extensions on Windows

Author: andyundso

.github/workflows/ci.yml

@@ -132,10 +132,10 @@ jobs:
         run: |
           $rubyArchitecture = (ruby -e "puts RbConfig::CONFIG['arch']").Trim()
           $gemVersion = (Get-Content VERSION).Trim()
-          $gemToInstall = "./tiny_tds-$gemVersion-$rubyArchitecture.gem"
+          $gemToUnpack = "./tiny_tds-$gemVersion-$rubyArchitecture.gem"
 
-          Write-Host "Looking to install $gemToInstall"
-          gem install --local --install-dir=./tmp "$gemToInstall"
+          Write-Host "Looking to unpack $gemToUnpack"
+          gem unpack --target ./tmp "$gemToUnpack"
 
           # Restore precompiled code
           $source = (Resolve-Path ".\tmp\gems\tiny_tds-$gemVersion-$rubyArchitecture\lib\tiny_tds").Path
@@ -257,10 +257,10 @@ jobs:
         run: |
           $rubyArchitecture = (ruby -e "puts RbConfig::CONFIG['arch']").Trim()
           $gemVersion = (Get-Content VERSION).Trim()
-          $gemToInstall = "./tiny_tds-$gemVersion-$rubyArchitecture.gem"
+          $gemToUnpack = "./tiny_tds-$gemVersion-$rubyArchitecture.gem"
 
-          Write-Host "Looking to install $gemToInstall"
-          gem install --local --install-dir=./tmp "$gemToInstall"
+          Write-Host "Looking to unpack $gemToUnpack"
+          gem unpack --target ./tmp "$gemToUnpack"
 
           # Restore precompiled code
           $source = (Resolve-Path ".\tmp\gems\tiny_tds-$gemVersion-$rubyArchitecture\lib\tiny_tds").Path