repo: setup copywrite stuff (#16)

* repo: add copywrite config

* repo: add mpl copyright headers

* ci: setup copywrite action
diff --git a/.copywrite.hcl b/.copywrite.hcl
new file mode 100644
index 0000000..87af51d
--- /dev/null
+++ b/.copywrite.hcl
@@ -0,0 +1,12 @@
+schema_version = 1
+
+project {
+  license          = "MPL-2.0"
+  copyright_holder = "The M1CPU Authors"
+  copyright_year   = 2022
+  header_ignore = [
+    ".golangci.yaml",
+    ".copywrite.hcl",
+    ".github/**",
+  ]
+}
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 933e3a2..b7b4ba4 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -1,6 +1,14 @@
 name: Run CI Tests
 on: [push]
 jobs:
+  run-copywrite:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+      - uses: hashicorp/setup-copywrite@v1.1.2
+      - name: verify copyright
+        run: |
+          copywrite headers --plan
   run-lint:
     runs-on: [macos-latest]
     steps:
diff --git a/cpu.go b/cpu.go
index 502a8cc..2bceceb 100644
--- a/cpu.go
+++ b/cpu.go
@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 //go:build darwin && arm64 && cgo
 
 package m1cpu
diff --git a/cpu_test.go b/cpu_test.go
index ed38452..afe8605 100644
--- a/cpu_test.go
+++ b/cpu_test.go
@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 //go:build darwin && arm64 && cgo
 
 package m1cpu
diff --git a/examples_test.go b/examples_test.go
index 9e57bd4..8548bcc 100644
--- a/examples_test.go
+++ b/examples_test.go
@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 package m1cpu
 
 import (
diff --git a/incompatible.go b/incompatible.go
index d425025..4b90403 100644
--- a/incompatible.go
+++ b/incompatible.go
@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 //go:build !darwin || !arm64 || !cgo
 
 package m1cpu
diff --git a/incompatible_test.go b/incompatible_test.go
index fe89ee5..1af52ef 100644
--- a/incompatible_test.go
+++ b/incompatible_test.go
@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 //go:build !darwin || !arm64 || !cgo
 
 package m1cpu