Try and remove lockfile wrangling

.github/workflows/ci.yaml

@@ -132,8 +132,8 @@ jobs:
       # XXX: Downgrade various dependencies to make them or their sub-dependencies MSRV compatible.
         run: |
           cargo generate-lockfile
-          cargo update -p proc-macro-crate --precise "1.3.0"
           cargo update -p regex --precise "1.9.6"
+        # cargo update -p proc-macro-crate --precise "1.3.0"
 
       - name: Clippy MSRV
         run: cargo clippy --features=rt-tokio-crypto-rust --all-targets --all -- -D clippy::dbg_macro -D warnings -F unused_must_use