chore(ci): add missing deps in generate package workflow (#13581)

Fixes the [Generate Package Versions
workflow](https://github.com/DataDog/dd-trace-py/actions/workflows/generate-package-versions.yml)
which was broken due to issues importing dependencies.

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Author: quinna-h

.github/workflows/generate-package-versions.yml

@@ -80,6 +80,8 @@ jobs:
           pip install packaging
           pip install requests
           pip install riot==0.20.1
+          pip install PyYAML
+          pip install ddtrace
 
       - name: Run regenerate-riot-latest
         run: scripts/regenerate-riot-latest.sh