docs(getting-started): fix Caddyfile plugin configuration #726

Job	Run time
Build Sablier docker image once and share it to E2E jobs	1m 38s
Build Caddy docker image once and share it to Caddy E2E jobs	1m 13s
Build ProxyWasm Plugin once and share it to ProxyWasm E2E jobs	42s
Build Caddy Sablier Plugin	19s
Build Traefik Sablier Plugin	14s
Run Sablier E2E tests for Proxywasm middleware on Apache APISIX (docker)	1m 16s
Run Sablier E2E tests for Proxywasm middleware on Envoy (docker)	1m 4s
Run Sablier E2E tests for Nginx NJS module with Sablier (docker)	1m 4s
Run Sablier E2E tests for Caddy middleware (docker)	1m 8s
Run Sablier E2E tests for Nginx NJS module with Sablier (docker_swarm)	2m 38s
Run Sablier E2E tests for Proxywasm middleware on Nginx (docker)	1m 25s
Run Sablier E2E tests for Caddy middleware (docker_swarm)	2m 45s
Run Sablier E2E tests for Traefik middleware (docker)	1m 12s
Run Sablier E2E tests for Traefik middleware (docker_swarm)	2m 44s
Run Sablier E2E tests for Traefik middleware (kubernetes)	1m 55s
	21m 17s

Provide feedback