servo: Merge #19201 - Some prerequisites to include gecko-media in Servo's dependency tree (from servo:bumps); r=jdm

These are commits that I keep rebasing every time #19152 bitrots.

It also includes the `cmake` bump that supports jobservers for real.

Source-Repo: https://github.com/servo/servo
Source-Revision: b74a89a14d51ac60fb7fb24881912c3e1829f34e

servo/python/tidy/servo_tidy/tidy.py

@@ -316,7 +316,7 @@ def check_flake8(file_name, contents):
 
 def check_lock(file_name, contents):
     def find_reverse_dependencies(name, content):
-        for package in itertools.chain([content.get("root", [])], content["package"]):
+        for package in itertools.chain([content.get("root", {})], content["package"]):
             for dependency in package.get("dependencies", []):
                 if dependency.startswith("{} ".format(name)):
                     yield package["name"], dependency