Update Zettlr to 1.8.7 (#7873)

* Update Zettlr to 1.8.7

* Removed ARM64 installer

* Removed trailing 0 in version to match file nam

Co-authored-by: Janek Kröger <janek@kroegerj.de>

manifests/Zettlr/Zettlr/1.8.7.yaml

@@ -0,0 +1,21 @@
+Id: Zettlr.Zettlr
+Publisher: Zettlr
+Name: Zettlr
+Version: 1.8.7
+License: GNU General Public License v3.0
+InstallerType: NULLSOFT
+LicenseUrl: https://github.com/Zettlr/Zettlr/blob/develop/LICENSE
+AppMoniker: Zettr
+Tags: "editor, markdow, writer"
+Description: 
+  Zettlr is a supercharged markdown editor that combines many writing editor features and
+  collect them in one application. It aims at speeding up your workflow and help you write
+  without any interruptions.
+Homepage: https://www.zettlr.com/
+Installers:
+  - Arch: x64
+    InstallerType: NULLSOFT
+    Url: https://github.com/Zettlr/Zettlr/releases/download/v1.8.7/Zettlr-1.8.7-x64.exe
+    Sha256: 6A3BB50A11475CD8F8C47A0B018153374F6B6DC6F2D9F955234109B62D94EE0F
+    Silent: /S
+ManifestVersion: 0.1.0