Update docs, file formatting and docker images (#766)

* docs: fix wrong licence link

* fix: add more formatting settings, reformat all

feat: add vscode extensions recommendations

* docs: update contributing documentation

* fix: remove unnecessary comment

it was due to broken checkout

* docs: rework installation section

it has been brought up few times, new style should be easier
to understand

* docs: update images provided by catthehacker

* docs: replace 18.04 with recent image

* fix: add final new line

Makefile

@@ -18,6 +18,9 @@ ifeq (true,$(HAS_TOKEN))
 	export GITHUB_TOKEN := $(shell cat ~/.config/github/token)
 endif
 
+.PHONY: pr
+pr: tidy format-all lint test
+
 .PHONY: build
 build:
 	go build -ldflags "-X main.version=$(VERSION)" -o dist/local/act main.go
@@ -26,6 +29,11 @@ build:
 format:
 	go fmt ./...
 
+.PHONY: format-all
+format-all:
+	go fmt ./...
+	npx prettier --write .
+
 .PHONY: test
 test:
 	go test ./...
@@ -37,11 +45,11 @@ lint-go:
 
 .PHONY: lint-js
 lint-js:
-	standard $(FIX)
+	npx standard $(FIX)
 
 .PHONY: lint-md
 lint-md:
-	markdownlint . $(FIX)
+	npx markdownlint . $(FIX)
 
 .PHONY: lint-rest
 lint-rest:
@@ -67,6 +75,10 @@ lint-fix: lint-md lint-go
 fix:
 	make lint-fix fix=true
 
+.PHONY: tidy
+tidy:
+	go mod tidy
+
 .PHONY: install
 install: build
 	@cp dist/local/act $(PREFIX)/bin/act