Pull "pick" action out of clangd/clangd

.github/actions/pick/action.yml

@@ -0,0 +1,15 @@
+name: 'Pick commit'
+description: 'Pick last successful commit from a repo'
+inputs:
+  repo:
+    description: 'Github repository e.g. llvm/llvm-project'
+    required: true
+  token:
+    description: 'Github auth token'
+    required: true
+outputs:
+  sha:
+    description: 'The SHA1 of the picked commit'
+runs:
+  using: 'node12'
+  main: 'index.js'

.github/actions/pick/index.js

@@ -0,0 +1,18 @@
+const core = require('@actions/core');
+const last = require('last-successful-gh-commit').default;
+try {
+  var parts = core.getInput('repo').split('/', 2);
+  last({
+    owner: parts[0],
+    name: parts[1],
+    token: core.getInput('token'),
+  })
+  .then(commit => core.setOutput('sha', commit.node.oid))
+  .catch(error => {
+    console.error(error);
+    core.setFailed(error.message);
+  });
+} catch (error) {
+  console.error(error);
+  core.setFailed(error.message);
+}