replace bors with mergify

.github/workflows/update-flake-lock.yml

@@ -24,4 +24,5 @@ jobs:
             ```
             {{ env.GIT_COMMIT_MESSAGE }}
             ```
-            bors merge
+          pr-labels: |                  # Labels to be set on the PR
+            merge-queue

.mergify.yml

@@ -0,0 +1,23 @@
+queue_rules:
+  - name: default
+    merge_conditions:
+      - check-success=Evaluate flake.nix
+      - check-success=check lint [x86_64-linux]
+      - check-success=devShell default [x86_64-linux]
+      - check-success=lockfile
+      - check-success=package default [x86_64-linux]
+      - check-success=package test-runner-stable [x86_64-linux]
+      - check-success=package test-runner-unstable [x86_64-linux]
+      - check-success=tests (ubuntu-latest, stable)
+      - check-success=tests (ubuntu-latest, unstable)
+defaults:
+  actions:
+    queue:
+      allow_merging_configuration_change: true
+pull_request_rules:
+  - name: merge using the merge queue
+    conditions:
+      - base=main
+      - label=merge-queue
+    actions:
+      queue: {}

bors.toml

@@ -1,11 +0,0 @@
-cut_body_after = "" # don't include text from the PR body in the merge commit message
-status = [
-  "Evaluate flake.nix",
-  "check lint [x86_64-linux]",
-  "devShell default [x86_64-linux]",
-  "package default [x86_64-linux]",
-  "package test-runner-stable [x86_64-linux]",
-  "package test-runner-unstable [x86_64-linux]",
-  "tests (ubuntu-latest, stable)",
-  "tests (ubuntu-latest, unstable)"
-]