ci: print slither version before running (#2992)

Makes it easier to debug when problems go wrong
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

.circleci/config.yml

@@ -127,7 +127,9 @@ jobs:
           working_directory: packages/contracts-bedrock
       - run:
           name: slither
-          command: yarn slither || exit 0
+          command: |
+            slither --version
+            yarn slither || exit 0
           working_directory: packages/contracts-bedrock
       - run:
           name: test