[2405] [SQUASH ON REBASE] Fix pip-requirement double listing (#1068)

## Description

regex is listed twice, once without a version, which causes Linux pip to
fail to install. This should be squashed with the CI commit on next
rebase:
92a21e3.

- [ ] Impacts functionality?
- **Functionality** - Does the change ultimately impact how firmware
functions?
- Examples: Add a new library, publish a new PPI, update an algorithm,
...
- [ ] Impacts security?
- **Security** - Does the change have a direct security impact on an
application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [ ] Breaking change?
- **Breaking change** - Will anyone consuming this change experience a
break
    in build or boot behavior?
- Examples: Add a new library class, move a module to a different repo,
call
    a function in a new library class in a pre-existing module, ...
- [ ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [ ] Includes documentation?
- **Documentation** - Does the change contain explicit documentation
additions
    outside direct code modifications (and comments)?
- Examples: Update readme file, add feature readme file, link to
documentation
    on an a separate Web page, ...

## How This Was Tested

Installing on Linux.

## Integration Instructions

N/A.

pip-requirements.txt

@@ -15,7 +15,6 @@
 edk2-pytool-library~=0.21.8 # MU_CHANGE
 edk2-pytool-extensions~=0.27.10 # MU_CHANGE
 antlr4-python3-runtime==4.13.1
-regex
 lcov-cobertura==2.0.2
 pygount==1.8.0 # MU_CHANGE
 toml==0.10.2 # MU_CHANGE