Fix docker-build script

The docker build is layered with a dependencies layer to cache
already compiled dependencies. To not cache the non-dependency code,
the last modified timestamp of the `lib.rs` files has to be updated.

If a new `lib.rs` file is introduced, its timestamp needs to be
updated as well. This was overlooked when introducing the
`canister_sig_utils` crate.

This PR makes the dockerfile more robust to touch _all_ the relevant
`lib.rs` files rather than specific ones.

Dockerfile

@@ -79,9 +79,7 @@ ARG II_INSECURE_REQUESTS=
 # DFX specific metadata for dfx deps
 ARG DFX_METADATA=
 
-RUN touch src/internet_identity/src/lib.rs
-RUN touch src/internet_identity_interface/src/lib.rs
-RUN touch src/canister_tests/src/lib.rs
+RUN touch src/*/src/lib.rs
 RUN npm ci
 
 RUN ./scripts/build ${DFX_METADATA:+"--dfx-metadata" "$DFX_METADATA"}
@@ -91,9 +89,7 @@ FROM deps as build_archive
 
 COPY . .
 
-RUN touch src/internet_identity_interface/src/lib.rs
-RUN touch src/archive/src/lib.rs
-RUN touch src/canister_tests/src/lib.rs
+RUN touch src/*/src/lib.rs
 
 RUN ./scripts/build --archive
 RUN sha256sum /archive.wasm.gz