Added support (and outputs) for semver builds and prereleases.

app/lib/tag.js

@@ -42,6 +42,14 @@ export default class Tag {
     return this._ref || ''
   }
 
+  get prerelease () {
+    return /([0-9\.]{5}(-[\w\.0-9]+)?)/i.test(this.version)
+  }
+
+  get build () {
+    return /([0-9\.]{5}(\+[\w\.0-9]+)?)/i.test(this.version)
+  }
+
   async getMessage () {
     if (this._message !== null) {
       return this._message

app/main.js

@@ -54,6 +54,8 @@ async function run () {
 
     core.warning(`Attempting to create ${tag.name} tag.`)
     core.setOutput('tagrequested', tag.name)
+    core.setOutput('prerelease', tag.prerelease ? 'yes' : 'no')
+    core.setOutput('build', tag.build ? 'yes' : 'no')
 
     // Check for existance of tag and abort (short circuit) if it already exists.
     if (await tag.exists()) {