docs: fix malformed URL scheme in docker resources (#545)

The compose_plantuml link used the scheme `hhttps://` (a doubled h) so
it does not resolve. The neighbouring funkwerk link on the same line
already uses `https://`. This corrects the scheme.

Author: latent-9

build-your-own-lab/docker_resources.md

@@ -27,7 +27,7 @@
 - [bocker](https://github.com/icy/bocker) (2) - Write Dockerfile completely in Bash. Extensible and simple. --> Reusable by [@icy](https://github.com/icy)
 - [box](https://github.com/box-builder/box) - Build Dockerfile images with a mruby DSL, includes flattening and layer manipulation
 - [Capitan](https://github.com/byrnedo/capitan) - Composable docker orchestration with added scripting support by [@byrnedo](https://github.com/byrnedo).
-- [compose_plantuml](hhttps://github.com/funkwerk/compose_plantuml) -  Generate Plantuml graphs from docker-compose files by [@funkwerk](https://github.com/funkwerk)
+- [compose_plantuml](https://github.com/funkwerk/compose_plantuml) -  Generate Plantuml graphs from docker-compose files by [@funkwerk](https://github.com/funkwerk)
 - [Composerize](https://github.com/magicmark/composerize) - Convert docker run commands into docker-compose files
 - [crowdr](https://github.com/polonskiy/crowdr) - Tool for managing multiple Docker containers (`docker-compose` alternative) by [@polonskiy](https://github.com/polonskiy/)
 - [docker-compose-graphviz](https://github.com/abesto/docker-compose-graphviz) - Turn a docker-compose.yml files into Graphviz .dot files by [@abesto](https://github.com/abesto)