Update portainer to version 2.21.0 (#1421)

portainer/docker-compose.yml

@@ -7,7 +7,7 @@ services:
       APP_PORT: 9000
 
   docker:
-    image: docker:24.0.5-dind@sha256:3c6e4dca7a63c9a32a4e00da40461ce067f255987ccc9721cf18ffa087bcd1ef
+    image: docker:27.2.0-dind@sha256:f9f72ad901a78f27be922b2d320bbc263174f12919c1b37e6a01f828fa904565
     privileged: true
     network_mode: host
     stop_grace_period: 1m
@@ -27,7 +27,7 @@ services:
       - ${APP_DATA_DIR}/data/docker:/data
 
   portainer:
-    image: portainer/portainer-ce:2.19.5@sha256:4a1ceadd7f7898d9190ee0a6d22234c4323aefd80e796e84f5e57127f74370f1
+    image: portainer/portainer-ce:2.21.0@sha256:a5e6d58c93bea2988b604f9c9b1afaa30dc213532dfd9beb7774429146276604
     command: --host unix:///var/run/docker.sock --admin-password-file=/default-password
     restart: on-failure
     volumes:

portainer/umbrel-app.yml

@@ -2,7 +2,7 @@ manifestVersion: 1
 id: portainer
 category: developer
 name: Portainer
-version: "2.19.5"
+version: "2.21.0"
 tagline: Run custom Docker containers on your Umbrel
 description: >-
   ⚠️ Make sure to only use named Docker volumes for your stacks and containers. Data in bind-mounted volumes
@@ -36,7 +36,7 @@ description: >-
   to restart automatically when the Portainer app is restarted or updated.
 
 
-  4. Web access to containers: Access your custom containers in your browser at umbrel.local:<mapped-port>. For example, for a container
+  4. Web access to containers: Access your custom containers in your browser at umbrel.local:PORT_NUMBER. For example, for a container
   with a web UI running on port 4545, navigate to umbrel.local:4545 to access it.
 website: https://portainer.io
 dependencies: []
@@ -51,8 +51,13 @@ path: ""
 defaultUsername: "admin"
 defaultPassword: "changeme"
 releaseNotes: >-
-  This update resolves a security vulnerability in Portainer, by creating uniform response time for login attempts.
-  More details can be found at https://github.com/advisories/GHSA-87x6-8m9v-g8c2
+  This is the first Long-Term Support (LTS) release of Portainer, which includes all changes up to the 2.20.3 release, as well as improvements to stability and scalability.
+
+
+  Key highlights:
+    - Improved overall stability
+    - Enhanced performance and reliability for larger environments
+    - Security updates to address critical and high vulnerabilities in dependencies
 
 
   Full release notes are found at https://github.com/portainer/portainer/releases.