Merge #3029

3029: Vendor Bundler 2.1.0 take 2 r=hsbt a=hsbt

# Description:

#3028 did point the wrong commit that is rubygems/bundler@4045ba4 . Bundler 2.1.0 was released at rubygems/bundler@683fe97

I update commit of submodule.
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# Tasks:

- [ ] Describe the problem / feature
- [ ] Write tests
- [ ] 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: Hiroshi SHIBATA <[email protected]>

Author: bundlerbot