Add woodpecker CI

.reuse/dep5

@@ -13,3 +13,8 @@ Source: https://pgpainless.org
 Files: gradle*
 Copyright: 2015 the original author or authors.
 License: Apache-2.0
+
+# Woodpecker build files
+Files: .woodpecker/*
+Copyright: 2022 the original author or authors.
+License: Apache-2.0

.woodpecker/.build.yml

@@ -0,0 +1,12 @@
+pipeline:
+  run:
+    image: gradle:7.5-jdk8
+    commands:
+      - git checkout $CI_COMMIT_BRANCH
+      # Code works
+      - gradle test
+      # Code is clean
+      - gradle check javadocAll
+      # Code has coverage
+      - gradle jacocoRootReport coveralls
+    secrets: [COVERALLS_REPO_TOKEN]

.woodpecker/.reuse.yml

@@ -0,0 +1,7 @@
+# Code is licensed properly
+# See https://reuse.software/
+pipeline:
+  reuse:
+    image: fsfe/reuse:latest
+    commands:
+      - reuse lint