fix: fix multiple versions bumps when version changes the string size

[jaysonsantos]

Description

As I've commented here the bug fix that fixes my bug also introduces a new one.
If you have a file that has many version = 1.0.9 and you bump to 1.1.10 every time you bump the version, the file increases 1 byte, and re.findall keeps a reference to the old string making every iteration point to a character back like (version, versio, versi, vers, and etc) to the point where it would move to previous likes and the check that makes sure that the current version is found on the current line fails.

Checklist

• Add test cases to all the changes you introduce
• Run ./script/format and ./script/test locally to ensure this change passes linter check and test
• Test the changes on the local machine manually
• Update the documentation for the changes

Expected behavior

All versions should be bumped no matter the size of the file and occurrences of a regex

Steps to Test This Pull Request

1 - Have a file with at least 8 version = 1.0.9 lines
2 - Bump version to 1.1.10 using file:version as the regex

Additional context

#372
#361

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@b94418b). Click here to learn what that means.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master     #374   +/-   ##
=========================================
  Coverage          ?   97.60%           
=========================================
  Files             ?       39           
  Lines             ?     1378           
  Branches          ?        0           
=========================================
  Hits              ?     1345           
  Misses            ?       33           
  Partials          ?        0           

Flag	Coverage Δ
unittests	97.60% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
commitizen/bump.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b94418b...f2cbf34. Read the comment docs.

[woile]

Looks good to me, feel free to merge @Lee-W

[Lee-W]

This one is interesting. 🤔 Didn't notice this might happen. Thanks, @jaysonsantos 👍👍👍