docs: drop deprecated compose version tag

README.md

@@ -102,7 +102,6 @@ Docker is the easiest way. There is the [official image here](https://hub.docker
 ```yaml
 # docker-compose.yml
 
-version: "3.8"
 
 services:
   cache:

README_ES.md

@@ -90,7 +90,6 @@ Docker es la manera más fácil. Aquí encontramos [la imagen oficial](https://h
 ```yaml
 # docker-compose.yml
 
-version: "3.8"
 
 services:
   cache:

README_zh-CN.md

@@ -77,7 +77,6 @@ Docker 是最简单的部署方式。这里是[官方镜像的地址](https://hu
 
 ```yaml
 # docker-compose.yml
-version: "3.8"
 
 services:
   cache:
@@ -115,7 +114,6 @@ services:
 - 域名 `example.org`
 
 ```yaml
-version: "3.8"
 
 networks:
   proxy:

examples/nginx/docker-compose.yaml

@@ -1,4 +1,3 @@
-version: '3.8'
 
 services:
   cache:

examples/scratch/README.md

@@ -25,7 +25,6 @@ This is a tiny guide to install cryptgeon on (probably) any unix system (and may
 ```yaml
 # docker-compose.yaml
 
-version: '3.8'
 services:
   traefik:
     image: traefik:2.6
@@ -100,7 +99,6 @@ Create another docker-compose.yaml file in another folder. We will assume that t
 ```
 
 ```yaml
-version: '3.8'
 
 networks:
   proxy:
@@ -155,7 +153,6 @@ docker-compose up -d
 ```yaml
 # docker-compose.yaml
 
-version: '3.8'
 
 services:
   watchtower:

examples/traefik/README.md

@@ -9,7 +9,6 @@ Assumptions:
 - Domain name `example.org`.
 
 ```yaml
-version: '3.8'
 
 networks:
   proxy: