Bump mozdebug from 0.3.0 to 0.3.1 in /tools

Bumps [mozdebug](https://wiki.mozilla.org/Auto-tools/Projects/Mozbase) from 0.3.0 to 0.3.1.

---
updated-dependencies:
- dependency-name: mozdebug
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

tools/wptrunner/requirements.txt

@@ -1,5 +1,5 @@
 html5lib==1.1
-mozdebug==0.3.0
+mozdebug==0.3.1
 mozinfo==1.2.3  # https://bugzilla.mozilla.org/show_bug.cgi?id=1621226
 mozlog==8.0.0
 mozprocess==1.3.1