Merge current branch v2.4 into master

docs/check.Dockerfile

@@ -8,8 +8,11 @@ RUN apk --no-cache --no-progress add \
     ruby-etc \
     ruby-ffi \
     ruby-json \
-    ruby-nokogiri
-RUN gem install html-proofer --version 3.13.0 --no-document -- --use-system-libraries
+    ruby-nokogiri \
+    ruby-dev \
+    build-base
+
+RUN gem install html-proofer --version 3.19.0 --no-document -- --use-system-libraries
 
 # After Ruby, some NodeJS YAY!
 RUN apk --no-cache --no-progress add \

docs/content/getting-started/configuration-overview.md

@@ -35,7 +35,7 @@ Since this configuration is specific to your infrastructure choices, we invite y
  
 ## The Static Configuration
 
-There are three different, **mutually exclusive** (e.g. you can use only one at the same time), ways to define static configuration options in Traefik:
+There are three different, **mutually exclusive** (i.e. you can use only one at the same time), ways to define static configuration options in Traefik:
 
 1. In a configuration file
 1. In the command-line arguments

docs/content/routing/providers/kubernetes-ingress.md

@@ -868,7 +868,7 @@ There are 3 ways to configure Traefik to use https to communicate with pods:
 
 1. If the service port defined in the ingress spec is `443` (note that you can still use `targetPort` to use a different port on your pod).
 1. If the service port defined in the ingress spec has a name that starts with https (such as `https-api`, `https-web` or just `https`).
-1. If the ingress spec includes the annotation `traefik.ingress.kubernetes.io/service.serversscheme: https`.
+1. If the service spec includes the annotation `traefik.ingress.kubernetes.io/service.serversscheme: https`.
 
 If either of those configuration options exist, then the backend communication protocol is assumed to be TLS,
 and will connect via TLS automatically.