Update version to 5.0a3. Update appcast.

Appcasts/netnewswire-beta.xml

@@ -6,6 +6,21 @@
         <description>Most recent NetNewsWire changes with links to updates.</description>
         <language>en</language>
 
+<item>
+          <title>NetNewsWire 5.0a3</title>
+            <description><![CDATA[
+							<p>Fixed crash happening only on macOS 10.15 beta. We owe Apple a bug report for this one.</p>
+							<p>Fixed a crash that could happen when finding a feed.</p>
+							<p>Skip showing error dialogs on automatic refreshes.</p>
+							<p>Immediately show the refresh progress bar when an OPML import to Feedbin starts.</p>
+							<p>Add ellipsis to Import from OPML and Export to OPML buttons.</p>
+							]]></description>
+            <pubDate>Mon, 10 Jun 2019 21:45:00 -0700</pubDate>
+            <enclosure url="https://ranchero.com/downloads/NetNewsWire5.0a3.zip" sparkle:version="2223" sparkle:shortVersionString="5.0a3" length="4689888" type="application/zip" />
+            <sparkle:minimumSystemVersion>10.14.4</sparkle:minimumSystemVersion>
+        </item>
+
+
 <item>
           <title>NetNewsWire 5.0a2</title>
             <description><![CDATA[

Mac/Resources/Info.plist

@@ -17,7 +17,7 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>5.0a2</string>
+	<string>5.0a3</string>
 	<key>CFBundleURLTypes</key>
 	<array>
 		<dict>