docs: pin link to sha (#968)

Signed-off-by: Mike Schore <[email protected]>
Signed-off-by: JP Simard <[email protected]>

mobile/STYLE.md

@@ -41,4 +41,5 @@ Additionally it can be installed as a commit hook with `pre-commit install`.
 to provide some enforced consistency, we've adopted the convention of defining the enum at the
 lowest applicable layer (core/bridge) of the library, and then declaring public `extern const`
 values defined in terms of the enumeration, to be shared across bridge and platform code. See,
-for example: https://github.com/lyft/envoy-mobile/blob/main/library/common/types/c_types.h#L25
+for example:
+https://github.com/lyft/envoy-mobile/blob/2a1b53427100d94878551b55bb564e9117f83fe6/library/common/types/c_types.h#L25