Try to fix CI.

Author: emilio

.github/workflows/main.yml

@@ -36,7 +36,7 @@ jobs:
           override: true
 
       - name: Downgrade phf to a version compatible with the MSRV
-        run: cargo update --package phf:0.11.0 --precise 0.10.1
+        run: cargo update --package phf --precise 0.10.1
         if: matrix.toolchain == '1.40.0'
 
       - name: Cargo build