Add release version lookup to About

frontend/src/sections/About.svelte

@@ -12,15 +12,41 @@
 
   export const open: boolean = false
   let version: string = ''
+  let newer: boolean = false
+  let availableVersion: string = ''
+  let availableSHA: string = ''
 
   function followLink(e: MouseEvent) {
     e.preventDefault()
     BrowserOpenURL((e.target as HTMLAnchorElement).href)
   }
 
+  async function getRelease() {
+    const url = 'https://api.github.com/repos/kettek/staxie/releases/latest'
+
+    try {
+      newer = false
+      const results = await (await fetch(url)).json()
+      const tag = await (await fetch(`https://api.github.com/repos/kettek/staxie/git/ref/tags/${results.tag_name}`)).json()
+      const sha = tag.object.sha
+
+      availableVersion = results.tag_name
+      availableSHA = sha
+
+      if (sha !== version) {
+        newer = true
+      } else {
+        newer = false
+      }
+    } catch (e) {
+      console.error(e)
+    }
+  }
+
   onMount(async () => {
     if ((window as any)['go']) {
       version = await Version()
+      await getRelease()
     } else {
       version = 'unknown browser'
     }
@@ -41,6 +67,12 @@
     <header>Version</header>
     <span>{version}</span>
   </article>
+  {#if availableVersion}
+    <article>
+      <header>Latest Version</header>
+      <Link on:click={followLink} href="https://github.com/kettek/staxie/releases/tag/{availableVersion}">{availableVersion} ({availableSHA})</Link>
+    </article>
+  {/if}
   <article>
     <header>Author</header>
     <Link on:click={followLink} href="https://kettek.net">kettek</Link>