Add manifest for Joplin 1.8.1 (#9610)

Co-authored-by: pluma9 <pluma9@google.com>

manifests/j/Joplin/Joplin/1.8.1/Joplin.Joplin.yaml

@@ -0,0 +1,22 @@
+PackageIdentifier: Joplin.Joplin
+PackageVersion: 1.8.1
+PackageName: Joplin
+Publisher: Joplin
+License: MIT
+LicenseUrl: https://github.com/laurent22/joplin/blob/master/LICENSE
+Moniker: joplin
+Tags:
+- joplin
+ShortDescription: Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks.
+PackageUrl: https://joplinapp.org/
+Installers:
+- Architecture: neutral
+  InstallerUrl: https://github.com/laurent22/joplin/releases/download/v1.8.1/Joplin-Setup-1.8.1.exe
+  InstallerSha256: 40AC861A0CEBCC4350707765039D30983AC8B84D097A6022082B684BC475ECD3
+  InstallerType: nullsoft
+  InstallerSwitches:
+    Silent: /S
+    SilentWithProgress: /S
+PackageLocale: en-US
+ManifestType: singleton
+ManifestVersion: 1.0.0