Bump mozdevice from 4.1.2 to 4.2.0 in /tools

Bumps [mozdevice](https://wiki.mozilla.org/Auto-tools/Projects/Mozbase) from 4.1.2 to 4.2.0.

---
updated-dependencies:
- dependency-name: mozdevice
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

tools/wptrunner/requirements_firefox.txt

@@ -1,6 +1,6 @@
 marionette_driver==3.4.0
 mozcrash==2.2.0
-mozdevice==4.1.2
+mozdevice==4.2.0
 mozinstall==2.1.0
 mozleak==0.2
 mozprofile==3.0.0