Merge pull request #17 from rex-rs/ci

 - ci: enforce commit sign-offs on pull requests
 - ci: update workflow path filters to exclude README.md
 - README: adding workflow status badges

Signed-off-by: Jinghao Jia <jinghao7@illinois.edu>

Author: jinghao-jia

.github/workflows/dco-check.yml

@@ -0,0 +1,10 @@
+name: DCO Check
+
+on:
+  pull_request:
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: KineticCafe/actions-dco@v1

.github/workflows/meson.yml

@@ -6,12 +6,14 @@ on:
       - docs/**
       - tools/**
       - flake.nix
+      - README.md
   pull_request:
     branches: [main]
     paths-ignore:
       - docs/**
       - tools/**
       - flake.nix
+      - README.md
 
 jobs:
   build_and_test:

.github/workflows/nix.yml

@@ -5,11 +5,13 @@ on:
     paths-ignore:
       - docs/**
       - tools/**
+      - README.md
   pull_request:
     branches: [main]
     paths-ignore:
       - docs/**
       - tools/**
+      - README.md
 
 jobs:
   build_and_test:

README.md

@@ -1,5 +1,9 @@
 # Rex kernel extensions
 
+[![CI](https://img.shields.io/github/actions/workflow/status/rex-rs/rex/.github%2Fworkflows%2Fmeson.yml?label=ci)](https://github.com/rex-rs/rex/actions)
+[![Nix](https://img.shields.io/github/actions/workflow/status/rex-rs/rex/.github%2Fworkflows%2Fnix.yml?label=ci-nix)](https://github.com/rex-rs/rex/actions)
+[![Gentoo](./docs/image/gentoo-badge3.svg)](https://www.gentoo.org)
+
 ```
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