docs: use codefences for syntax highlighting

Author: NickLarsenNZ

README.md

@@ -6,28 +6,36 @@ Version: 0.0.9
 
 We recommend to use [pipx](https://pypa.github.io/pipx/):
 
-    pipx install beku-stackabletech
+```sh
+pipx install beku-stackabletech
+```
 
 But you can also use `pip`:
 
-    # from PyPI
-    pip install beku-stackabletech
-    # from GitHub
-    pip install git+https://github.com/stackabletech/beku.py.git@master
+```sh
+# from PyPI
+pip install beku-stackabletech
+# from GitHub
+pip install git+https://github.com/stackabletech/beku.py.git@master
+```
 
 ## Usage
 
-    cd <stackable operator directory>
-    rm -rf tests/_work && beku
-    cd tests/_work && kubectl kuttl test
+```sh
+cd <stackable operator directory>
+rm -rf tests/_work && beku
+cd tests/_work && kubectl kuttl test
+```
 
 Also see the `examples` folder.
 
 ## Description
 
 Fast Kuttl tests expander for Stackable integration tests.
 
-    beku -i tests/test-definition.yaml -t tests/templates/kuttl -k tests/kuttl-test.yaml.jinja2 -o tests/_work
+```sh
+beku -i tests/test-definition.yaml -t tests/templates/kuttl -k tests/kuttl-test.yaml.jinja2 -o tests/_work
+```
 
 ## Release a new version
 
@@ -41,6 +49,8 @@ Update the CHANGELOG.
 Commit and tag.
 Build and publish:
 
-    rm -rf dist/
-    python -m build --wheel .
-    twine upload dist/*
+```sh
+rm -rf dist/
+python -m build --wheel .
+twine upload dist/*
+```