feat: CI: run tests on nightly rust

mockall lib requires nightly toolchain

.woodpecker.yml

@@ -1,5 +1,5 @@
 steps:
-  build_and_test:
+  test:
     image: rust
     when:
       event: [push, pull_request, tag, deployment]
@@ -11,9 +11,17 @@ steps:
       - rustup toolchain install nightly
       - rustup component add rustfmt
       - rustup component add clippy
+      - rustup override set nightly
       - make db.migrate
       - make lint
       - make test
+
+  build_binary:
+    image: rust
+    when:
+      event: [push, pull_request, tag, deployment]
+    commands:
+      - rustup override set stable
       - make release
 
   build_docker_img: