ci: switch from GitHub action to drone

I'm running my own CI at ci.fcuny.net using drone for now. I've spare
compute capacity at home, and it's way faster than the GHA runners.

For now I'm losing the following:
- dependabot: that's a GitHub only function, I'll need to figure out
  something
- nix flake update: I'll need to figure out a way to update flakes on a
  regular basis, probably a custom script to take care of that

4 files changed, 37 insertions, 60 deletions

diff --git a/src/x509-info/.drone.yml b/src/x509-info/.drone.yml
new file mode 100644
index 0000000..0816988
--- /dev/null
+++ b/src/x509-info/.drone.yml
@@ -0,0 +1,35 @@
+kind: pipeline
+type: docker
+name: checks
+
+trigger:
+  event:
+    - push
+    - pull_request
+    - cron
+
+steps:
+  - name: Run checks
+    image: nixpkgs/nix-flakes:nixos-22.05
+    commands:
+      - nix develop --command cargo fmt --check
+      - nix develop --command cargo-deny check
+      - nix develop --command cargo clippy -- -D warnings
+---
+kind: pipeline
+type: docker
+name: build
+
+trigger:
+  event:
+    - push
+    - pull_request
+    - cron
+
+steps:
+  - name: Run tests and build
+    image: nixpkgs/nix-flakes:nixos-22.05
+    commands:
+      - nix develop --command cargo test
+      - nix build .
+      - nix run . -- fcuny.net
diff --git a/src/x509-info/.github/dependabot.yml b/src/x509-info/.github/dependabot.yml
deleted file mode 100644
index 2b2ebcf..0000000
--- a/src/x509-info/.github/dependabot.yml
+++ /dev/null
@@ -1,11 +0,0 @@
-version: 2
-updates:
-- package-ecosystem: cargo
-  directory: "/"
-  schedule:
-    interval: daily
-  open-pull-requests-limit: 10
-- package-ecosystem: "github-actions"
-  directory: "/"
-  schedule:
-    interval: "weekly"
diff --git a/src/x509-info/.github/workflows/build.yml b/src/x509-info/.github/workflows/build.yml
deleted file mode 100644
index 0d3d439..0000000
--- a/src/x509-info/.github/workflows/build.yml
+++ /dev/null
@@ -1,49 +0,0 @@
-name: x509-info CI
-
-on:
-  push:
-
-jobs:
-  check:
-    name: Check
-    runs-on: ubuntu-latest
-    steps:
-      - name: git checkout
-        uses: actions/checkout@v3
-      - name: install nix
-        uses: cachix/install-nix-action@v17
-      # This is a workaround for https://github.com/oxalica/rust-overlay/issues/54,
-      # avoiding link errors when running cargo commands with `nix develop`.
-      - name: Remove existing binaries from ~/.cargo/bin
-        run: rm --recursive --force --verbose ~/.cargo/bin
-      - name: check rust formatting
-        run: nix develop --command cargo fmt --check
-      - name: audit rust code
-        run: nix develop --command cargo-deny check
-      - name: clippy
-        run: nix develop --command cargo clippy -- -D warnings
-
-  test_and_build:
-    name: Test and build
-    runs-on: ubuntu-latest
-    steps:
-      - name: git checkout
-        uses: actions/checkout@v3
-      - name: install nix
-        uses: cachix/install-nix-action@v17
-      - name: Set up Rust cache
-        uses: actions/cache@v3
-        with:
-          path: |
-            ~/.cargo/bin/
-            ~/.cargo/registry/index/
-            ~/.cargo/registry/cache/
-            ~/.cargo/git/db/
-            target/
-          key: x509-info-app-${{ hashFiles('**/Cargo.lock') }}
-      - name: test
-        run: nix develop --command cargo test
-      - name: build
-        run: nix build .
-      - name: validate
-        run: nix run . -- fcuny.net
diff --git a/src/x509-info/README.md b/src/x509-info/README.md
index c8a1090..39fc564 100644
--- a/src/x509-info/README.md
+++ b/src/x509-info/README.md
@@ -1,5 +1,7 @@
 # x509-info
 
+[![Build Status](https://ci.fcuny.net/api/badges/fcuny/x509-info/status.svg)](https://ci.fcuny.net/fcuny/x509-info)
+
 At this point it's pretty clear that I'll never remember the syntax for `openssl` to show various information about a certificate. At last I will not have to google for that syntax ever again.
 
 ``` shell