Updates to make vagrant-spec work in CI

* The vagrant-spec gem is installed as part of bundle install so
   there's no need to install it separately. Remove those extra steps
   and invoke it with bundle exec instead.
 * The binstub for vagrant does not work with `--standalone` in CI, but
   the one generated w/o `--standalone` works fine. This also seems to
   work in dev, so we'll just switch to that one.
 * Fetch all tags in CI to make sure we're getting proper version
   numbers in our build (based off `git describe`).

.github/workflows/go-spectest.yml

@@ -27,6 +27,9 @@ jobs:
         uses: actions/checkout@v2
         with:
           submodules: 'recursive'
+          # Also fetch all tags, since we need our version number in the build
+          # to be based off a tag
+          fetch-depth: 0
       - name: Setup Go
         uses: actions/setup-go@v2
         with:
@@ -46,17 +49,13 @@ jobs:
         env:
           HASHIBOT_USERNAME: ${{ secrets.HASHIBOT_USERNAME }}
           HASHIBOT_TOKEN: ${{ secrets.HASHIBOT_TOKEN }}
-      - name: Get vagrant-spec repo
-        uses: actions/checkout@v2
-        with:
-          repository: 'hashicorp/vagrant-spec'
-          path: vagrant-spec
-      - name: Install and run vagrant-spec
+      - name: Add binstubs to path
         run: |
-          pushd vagrant-spec
-          gem build vagrant-spec.gemspec
-          gem install vagrant-spec-0.0.1.gem
-          popd
-          VAGRANT_PATH="$GITHUB_WORKSPACE/vagrant" vagrant-spec test --components=cli/version --config test/vagrant-spec/configs/vagrant-spec.config.virtualbox.rb
+          echo "$PWD/binstubs" >> $GITHUB_PATH
+        env:
+          VAGRANT_SPEC_BOX: "hashicorp/bionic64"
+      - name: Run vagrant-spec
+        run: |
+          VAGRANT_PATH="$GITHUB_WORKSPACE/vagrant" bundle exec vagrant-spec test --components=cli/version --config test/vagrant-spec/configs/vagrant-spec.config.virtualbox.rb
         env:
           VAGRANT_SPEC_BOX: "hashicorp/bionic64"

binstubs/vagrant

@@ -1,4 +1,6 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
+
 #
 # This file was generated by Bundler.
 #
@@ -7,8 +9,21 @@
 #
 
 require "pathname"
-path = Pathname.new(__FILE__)
-$:.unshift File.expand_path "../..", path.realpath
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile",
+  Pathname.new(__FILE__).realpath)
 
+bundle_binstub = File.expand_path("../bundle", __FILE__)
+
+if File.file?(bundle_binstub)
+  if File.read(bundle_binstub, 300) =~ /This file was generated by Bundler/
+    load(bundle_binstub)
+  else
+    abort("Your `bin/bundle` was not generated by Bundler, so this binstub cannot run.
+Replace `bin/bundle` by running `bundle binstubs bundler --force`, then run this command again.")
+  end
+end
+
+require "rubygems"
 require "bundler/setup"
-load File.expand_path "../../bin/vagrant", path.realpath
+
+load Gem.bin_path("vagrant", "vagrant")