test: Remove deprecated pipeline instruction

.woodpecker/lint.yml

@@ -1,4 +1,4 @@
-pipeline:
+steps:
   lint_ruff:
     image: python
     commands:

.woodpecker/static_analysis.yml

@@ -1,4 +1,4 @@
-pipeline:
+steps:
   pyright:
     image: nikolaik/python-nodejs
     commands:

.woodpecker/test.yml

@@ -1,6 +1,7 @@
-branches: main
+when:
+  branch: main
 
-pipeline:
+steps:
   pytest:
     image: ghcr.io/withlogicco/poetry:1.5.1
     commands: