chore(deps): bump default drone-ssh version to 1.8.4

- Update the default binary version from 1.8.2 to 1.8.4
- Sync the version reference in the development guide

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CLAUDE.md

@@ -162,7 +162,7 @@ Or use ED25519 keys instead (preferred).
 
 The action pins to specific drone-ssh versions via:
 
-- Default: `DRONE_SSH_VERSION="1.8.2"` in `entrypoint.sh`
+- Default: `DRONE_SSH_VERSION="1.8.4"` in `entrypoint.sh`
 - Override: Users can specify `version` input parameter
 
 Update the default version when new drone-ssh releases are available.

entrypoint.sh

@@ -6,7 +6,7 @@ export GITHUB="true"
 
 GITHUB_ACTION_PATH="${GITHUB_ACTION_PATH%/}"
 DRONE_SSH_RELEASE_URL="${DRONE_SSH_RELEASE_URL:-https://github.com/appleboy/drone-ssh/releases/download}"
-DRONE_SSH_VERSION="${DRONE_SSH_VERSION:-1.8.2}"
+DRONE_SSH_VERSION="${DRONE_SSH_VERSION:-1.8.4}"
 
 # Error codes
 readonly ERR_UNKNOWN_PLATFORM=2