fix: sum256 the container name so derivations do not overflow (#191)

For instance, the volume name derived from the workflow name may exceed the file system limit when the container name it is derived from is too long.

Fixes forgejo/runner#152

Reviewed-on: https://code.forgejo.org/forgejo/act/pulls/191
Reviewed-by: Michael Kriese <michael.kriese@gmx.de>
Co-authored-by: Earl Warren <contact@earl-warren.org>
Co-committed-by: Earl Warren <contact@earl-warren.org>

act/common/sha256_test.go

@@ -0,0 +1,13 @@
+// Copyright 2025 The Forgejo Authors
+// SPDX-License-Identifier: MIT
+package common
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSha256(t *testing.T) {
+	assert.Equal(t, "3fc9b689459d738f8c88a3a48aa9e33542016b7a4052e001aaa536fca74813cb", Sha256("something"))
+}