Install specific bundler version when exact version is given

Fixes #138

Add Ruby 3.0.0 on Windows

v1.61.1

Ensure no \r are added when running generate-windows-versions.rb on W…

Add Ruby 3.0.0

v1.61.0

Add Ruby 3.0.0

Fix caching for gemfile under sub-directory

• Fixes #131

Add Ruby 3.0.0-rc1

v1.60.0

Add 3.0.0-rc1

Fix cache saving on Windows and add jruby-9.2.14.0

Fixes #102

Support a specific version for the bundler input, and use the exact Bundler version from the lockfile if provided

• Fixes #123

Only set $BUNDLER_VERSION when needed

• Fixes #122

Add Ruby 3.0.0-preview2

• Fixes #121

Do not export BUNDLER_VERSION

• Fixes #119