Added Plex Media Server version 1.21.1.3876. (#6284)

manifests/Plex/PlexMediaServer/1.21.1.3876.yaml

@@ -0,0 +1,25 @@
+Id: Plex.PlexMediaServer
+Publisher: Plex
+Name: Plex Media Server
+Author: Plex
+Description: Host media content in Plex Media Server.
+AppMoniker: plexmediaserver
+Tags: mediaserver, streaming, video, music
+
+Homepage: https://www.plex.tv/media-server-downloads/
+License: Copyright © 2020, Plex
+LicenseUrl: https://www.plex.tv/about/privacy-legal/plex-terms-of-service/
+
+MinOSVersion: 10.0.0.0
+#Channel: stable                # Channel is not supported in this preview (5/24/2020)
+Version: 1.21.1.3876
+
+InstallerType: nullsoft
+Installers:
+  - Arch: x86
+    Url: https://downloads.plex.tv/plex-media-server-new/1.21.1.3876-3c3adfcb4/windows/PlexMediaServer-1.21.1.3876-3c3adfcb4-x86.exe
+    Sha256: AA63F2FAEC30C5174D32A5D9FEED19854F1588D8DAAB44B77413334E2B78C0CB
+    ProductCode: "{4a5565be-c707-413a-baa1-d5eccde17706}"
+    Scope: machine
+    Language: en-US
+