build(deps): bump dependencies to the latest released versions (#50)

Co-authored-by: slack-samples[bot] <169401055+slack-samples[bot]@users.noreply.github.com>

Author: slack-samples[bot]

.slack/hooks.json

@@ -1,5 +1,5 @@
 {
   "hooks": {
-    "get-hooks": "deno run -q --allow-read --allow-net https://deno.land/x/deno_slack_hooks@1.4.0/mod.ts"
+    "get-hooks": "deno run -q --allow-read --allow-net https://deno.land/x/deno_slack_hooks@1.5.0/mod.ts"
   }
 }

deno.jsonc

@@ -30,8 +30,8 @@
     "test": "deno fmt --check && deno lint && deno test --allow-read"
   },
   "imports": {
-    "@std/assert": "jsr:@std/assert@^1.0.13",
-    "@std/testing": "jsr:@std/testing@^1.0.12",
+    "@std/assert": "jsr:@std/assert@^1.0.15",
+    "@std/testing": "jsr:@std/testing@^1.0.16",
     "deno-slack-sdk/": "https://deno.land/x/deno_slack_sdk@2.15.1/",
     "deno-slack-api/": "https://deno.land/x/deno_slack_api@2.8.0/"
   }