feat(step-ca): update step-ca version from 0.29.0 to 0.30.2

update note:
- step-ca container doesn't support $PWDPATH anymore
- add --password-file argument to exec

config/services/containers/infra/ca/ca.container.j2

@@ -22,14 +22,17 @@ Volume=%h/containers/ca/db:/home/step/db:rw
 Volume=%h/containers/ca/templates:/home/step/templates:rw
 
 Environment="TZ=Asia/Seoul"
-Environment="PWDPATH=/run/secrets/STEP_CA_PASSWORD"
+# Since 0.30.0, Docker CMD no longer expands PWDPATH.
+#Environment="PWDPATH=/run/secrets/STEP_CA_PASSWORD"
 
 Secret=STEP_CA_PASSWORD,target=/run/secrets/STEP_CA_PASSWORD
 
+Exec=/usr/local/bin/step-ca --password-file /run/secrets/STEP_CA_PASSWORD /home/step/config/ca.json
+
 [Service]
 Restart=always
 RestartSec=10s
 TimeoutStopSec=120
 
 [Install]
-WantedBy=default.target
+WantedBy=default.target