Fix yamllint recommendations

testing/resources/conda_hooks_repo/.pre-commit-hooks.yaml

@@ -1,10 +1,13 @@
--   id: sys-exec
-    name: sys-exec
-    entry: python -c 'import os; import sys; print(sys.executable.split(os.path.sep)[-2]) if os.name == "nt" else print(sys.executable.split(os.path.sep)[-3])'
-    language: conda
-    files: \.py$
--   id: additional-deps
-    name: additional-deps
-    entry: python
-    language: conda
-    files: \.py$
+---
+
+- id: sys-exec
+  name: sys-exec
+  entry: python -c 'import os; import sys; print(sys.executable.split(os.path.sep)[-2]) if os.name == "nt" else print(sys.executable.split(os.path.sep)[-3])'
+  language: conda
+  files: \.py$
+
+- id: additional-deps
+  name: additional-deps
+  entry: python
+  language: conda
+  files: \.py$

testing/resources/conda_hooks_repo/environment.yml

@@ -1,3 +1,5 @@
+---
+
 channels:
   - conda-forge
   - defaults