chore: update to ameba 1.7.0 and adapt most of the code to it (#6082)

* chore: update to ameba 1.7.0 and adapt most of the code to it

* forgot to add this to build ameba into the ./bin directory for use, as ameba does not longer offer a postinstall script

* forgot to update ameba in the shards files

* remove leftover : in rescue

* Use ameba linter action instead of installing it with shards

.github/workflows/ci.yml

@@ -146,7 +146,6 @@ jobs:
         with:
           path: |
             ./lib
-            ./bin
           key: shards-${{ hashFiles('shard.lock') }}-${{ steps.lint_step_install_crystal.outputs.crystal }}
 
       - name: Install Shards
@@ -164,4 +163,4 @@ jobs:
           fi
 
       - name: Run Ameba linter
-        run: bin/ameba
+        uses: crystal-ameba/github-action@v1