Merge #3028

3028: Vendor bundler 2.1 r=hsbt a=deivid-rodriguez

# Description:

We should release bundler 2.1 and include it in rubygems before releasing rubygems 3.1

# Tasks:

- [x] Describe the problem / feature
- [ ] Write tests
- [x] Write code to solve the problem
- [ ] Get code review from coworkers / friends

I will abide by the [code of conduct](https://github.com/rubygems/rubygems/blob/master/CODE_OF_CONDUCT.md).


Co-authored-by: David Rodríguez <[email protected]>

Author: 2 people

Manifest.txt

@@ -79,7 +79,6 @@ bundler/lib/bundler/fetcher/index.rb
 bundler/lib/bundler/friendly_errors.rb
 bundler/lib/bundler/gem_helper.rb
 bundler/lib/bundler/gem_helpers.rb
-bundler/lib/bundler/gem_remote_fetcher.rb
 bundler/lib/bundler/gem_tasks.rb
 bundler/lib/bundler/gem_version_promoter.rb
 bundler/lib/bundler/gemdeps.rb
@@ -172,7 +171,6 @@ bundler/lib/bundler/vendor/connection_pool/lib/connection_pool/monotonic_time.rb
 bundler/lib/bundler/vendor/connection_pool/lib/connection_pool/timed_stack.rb
 bundler/lib/bundler/vendor/connection_pool/lib/connection_pool/version.rb
 bundler/lib/bundler/vendor/fileutils/lib/fileutils.rb
-bundler/lib/bundler/vendor/fileutils/lib/fileutils/version.rb
 bundler/lib/bundler/vendor/molinillo/lib/molinillo.rb
 bundler/lib/bundler/vendor/molinillo/lib/molinillo/compatibility.rb
 bundler/lib/bundler/vendor/molinillo/lib/molinillo/delegates/resolution_state.rb
@@ -209,13 +207,13 @@ bundler/lib/bundler/vendor/thor/lib/thor/actions/inject_into_file.rb
 bundler/lib/bundler/vendor/thor/lib/thor/base.rb
 bundler/lib/bundler/vendor/thor/lib/thor/command.rb
 bundler/lib/bundler/vendor/thor/lib/thor/core_ext/hash_with_indifferent_access.rb
-bundler/lib/bundler/vendor/thor/lib/thor/core_ext/io_binary_read.rb
 bundler/lib/bundler/vendor/thor/lib/thor/error.rb
 bundler/lib/bundler/vendor/thor/lib/thor/group.rb
 bundler/lib/bundler/vendor/thor/lib/thor/invocation.rb
 bundler/lib/bundler/vendor/thor/lib/thor/line_editor.rb
 bundler/lib/bundler/vendor/thor/lib/thor/line_editor/basic.rb
 bundler/lib/bundler/vendor/thor/lib/thor/line_editor/readline.rb
+bundler/lib/bundler/vendor/thor/lib/thor/nested_context.rb
 bundler/lib/bundler/vendor/thor/lib/thor/parser.rb
 bundler/lib/bundler/vendor/thor/lib/thor/parser/argument.rb
 bundler/lib/bundler/vendor/thor/lib/thor/parser/arguments.rb
@@ -229,10 +227,24 @@ bundler/lib/bundler/vendor/thor/lib/thor/shell/color.rb
 bundler/lib/bundler/vendor/thor/lib/thor/shell/html.rb
 bundler/lib/bundler/vendor/thor/lib/thor/util.rb
 bundler/lib/bundler/vendor/thor/lib/thor/version.rb
+bundler/lib/bundler/vendor/uri/lib/uri.rb
+bundler/lib/bundler/vendor/uri/lib/uri/common.rb
+bundler/lib/bundler/vendor/uri/lib/uri/file.rb
+bundler/lib/bundler/vendor/uri/lib/uri/ftp.rb
+bundler/lib/bundler/vendor/uri/lib/uri/generic.rb
+bundler/lib/bundler/vendor/uri/lib/uri/http.rb
+bundler/lib/bundler/vendor/uri/lib/uri/https.rb
+bundler/lib/bundler/vendor/uri/lib/uri/ldap.rb
+bundler/lib/bundler/vendor/uri/lib/uri/ldaps.rb
+bundler/lib/bundler/vendor/uri/lib/uri/mailto.rb
+bundler/lib/bundler/vendor/uri/lib/uri/rfc2396_parser.rb
+bundler/lib/bundler/vendor/uri/lib/uri/rfc3986_parser.rb
+bundler/lib/bundler/vendor/uri/lib/uri/version.rb
 bundler/lib/bundler/vendored_fileutils.rb
 bundler/lib/bundler/vendored_molinillo.rb
 bundler/lib/bundler/vendored_persistent.rb
 bundler/lib/bundler/vendored_thor.rb
+bundler/lib/bundler/vendored_uri.rb
 bundler/lib/bundler/version.rb
 bundler/lib/bundler/version_ranges.rb
 bundler/lib/bundler/vlad.rb