Update crates and GHA (#6980)

Updated all crates which are possible.

Updated all GitHub Actions to their latest version.
There was a supply-chain attack on the trivy action to which we were not exposed since we were using pinned sha hashes.
The latest version v0.35.0 is not vulnerable and that version will be used with this commit.

Also removed `dtolnay/rust-toolchain` as suggested by zizmor and adjusted the way to install the correct toolchain.
Since this GitHub Action did not used any version tagging, it was also cumbersome to update.

Signed-off-by: BlackDex <black.dex@gmail.com>

src/api/admin.rs

@@ -637,7 +637,6 @@ use cached::proc_macro::cached;
 /// Cache this function to prevent API call rate limit. Github only allows 60 requests per hour, and we use 3 here already
 /// It will cache this function for 600 seconds (10 minutes) which should prevent the exhaustion of the rate limit
 /// Any cache will be lost if Vaultwarden is restarted
-use std::time::Duration; // Needed for cached
 #[cached(time = 600, sync_writes = "default")]
 async fn get_release_info(has_http_access: bool) -> (String, String, String) {
     // If the HTTP Check failed, do not even attempt to check for new versions since we were not able to connect with github.com anyway.