Add RusherHack Speedometer plugin entry

Added RusherHack Speedometer plugin with details.

Author: GarlicRot

data/plugins-and-themes.yml

@@ -1549,6 +1549,18 @@ plugins:
     is_core: false
     mc_versions: 1.21.4
     jar_url: https://github.com/icaema/rusherhacks-stopwatch/releases/download/v1.0.0/stopwatch-1.0.0.jar
+  - name: RusherHack Speedometer
+    repo: tillay-rh-plugins/rusherhack-speedometer
+    description: Adds customizable speed HUD elements including a speed readout with unit conversions (e.g., miles/hour, bananas/second, lightyears/year) and a Mach meter displaying speed relative to the speed of sound.
+    creator:
+      name: tillay
+      url: https://github.com/tillay
+      avatar: https://github.com/tillay.png?size=20
+    latest_release_tag: v1.0.0
+    screenshots: []
+    is_core: false
+    mc_versions: 1.21.4
+    jar_url: https://github.com/tillay-rh-plugins/rusherhack-speedometer/releases/download/v1.0.0-5872158a4f44c1c69362b63bdc617515a45ca15c/speedometer-1.0.0.jar
 themes:
   - name: rusherNodusTheme
     repo: bakjedev/rusherNodusTheme