mach: Do not track the uv.lock file (#42214)

This is a temporary fix until a more complete solution, such
as the one from #42169, works consistently.

Testing: This should be tested by the CI run.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

.gitignore

@@ -30,6 +30,10 @@ servo.pftrace
 webrender-captures/
 /screenshots
 
+# We do not check this in for the moment, until the issue from
+# https://github.com/servo/servo/pull/42169 can be addressed.
+uv.lock
+
 # Allow CSV files to be used as resources in tests
 !/tests/**/*.csv
 
@@ -73,4 +77,4 @@ support/macos/Brewfile.lock.json
 .envrc
 
 # Justfiles
-justfile
+justfile