docs(release): update doc version from 1.8.1 to 1.8.2 #775

Job	Run time
Build Sablier docker image once and share it to E2E jobs	1m 43s
Build Caddy docker image once and share it to Caddy E2E jobs	1m 15s
Build ProxyWasm Plugin once and share it to ProxyWasm E2E jobs	30s
Build Traefik Sablier Plugin	12s
Build Caddy Sablier Plugin	12s
Run Sablier E2E tests for Proxywasm middleware on Apache APISIX (docker)	1m 18s
Run Sablier E2E tests for Nginx NJS module with Sablier (docker)	1m 22s
Run Sablier E2E tests for Caddy middleware (docker)	1m 17s
Run Sablier E2E tests for Nginx NJS module with Sablier (docker_swarm)	2m 22s
Run Sablier E2E tests for Traefik middleware (docker)	1m 16s
Run Sablier E2E tests for Caddy middleware (docker_swarm)	2m 18s
Run Sablier E2E tests for Traefik middleware (docker_swarm)	2m 43s
Run Sablier E2E tests for Proxywasm middleware on Envoy (docker)	1m 13s
Run Sablier E2E tests for Traefik middleware (kubernetes)	1m 46s
Run Sablier E2E tests for Proxywasm middleware on Nginx (docker)	1m 34s
	21m 1s

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