Detect WSL and only use more then 1 thread when NOT on WSL

Based on microsoft/WSL#4555 via
#374 which has
a ton more possibilities to detect WSL.

Makefile

@@ -24,30 +24,36 @@ else
 		"ghcr.io/wyrihaximusnet/php:${PHP_VERSION}-nts-alpine3.12${SLIM_DOCKER_IMAGE}-dev"
 endif
 
+ifneq (,$(findstring icrosoft,$(shell cat /proc/version)))
+    THREADS=1
+else
+    THREADS=$(shell nproc)
+endif
+
 all: ## Runs everything ###
 	@grep -E '^[a-zA-Z0-9_-]+:.*?## .*$$' $(MAKEFILE_LIST) | grep -v "###" | awk 'BEGIN {FS = ":.*?## "}; {printf "%s\n", $$1}' | xargs --open-tty $(MAKE)
 
 syntax-php: ## Lint PHP syntax
 	$(DOCKER_RUN) vendor/bin/parallel-lint --exclude vendor .
 
 cs-fix: ## Fix any automatically fixable code style issues
-	$(DOCKER_RUN) vendor/bin/phpcbf --parallel=$(shell nproc) --cache=./var/.phpcs.cache.json --standard=./etc/qa/phpcs.xml || $(DOCKER_RUN) vendor/bin/phpcbf --parallel=$(shell nproc) --cache=./var/.phpcs.cache.json --standard=./etc/qa/phpcs.xml || $(DOCKER_RUN) vendor/bin/phpcbf --parallel=$(shell nproc) --cache=./var/.phpcs.cache.json --standard=./etc/qa/phpcs.xml -vvvv
+	$(DOCKER_RUN) vendor/bin/phpcbf --parallel=$(THREADS) --cache=./var/.phpcs.cache.json --standard=./etc/qa/phpcs.xml || $(DOCKER_RUN) vendor/bin/phpcbf --parallel=$(THREADS) --cache=./var/.phpcs.cache.json --standard=./etc/qa/phpcs.xml || $(DOCKER_RUN) vendor/bin/phpcbf --parallel=$(THREADS) --cache=./var/.phpcs.cache.json --standard=./etc/qa/phpcs.xml -vvvv
 
 cs: ## Check the code for code style issues
-	$(DOCKER_RUN) vendor/bin/phpcs --parallel=$(shell nproc) --cache=./var/.phpcs.cache.json --standard=./etc/qa/phpcs.xml
+	$(DOCKER_RUN) vendor/bin/phpcs --parallel=$(THREADS) --cache=./var/.phpcs.cache.json --standard=./etc/qa/phpcs.xml
 
 stan: ## Run static analysis (PHPStan)
 	$(DOCKER_RUN) vendor/bin/phpstan analyse src tests --level max --ansi -c ./etc/qa/phpstan.neon
 
 psalm: ## Run static analysis (Psalm)
-	$(DOCKER_RUN) vendor/bin/psalm --threads=$(shell nproc) --shepherd --stats --config=./etc/qa/psalm.xml
+	$(DOCKER_RUN) vendor/bin/psalm --threads=$(THREADS) --shepherd --stats --config=./etc/qa/psalm.xml
 
 unit-testing: ## Run tests
 	$(DOCKER_RUN) vendor/bin/phpunit --colors=always -c ./etc/qa/phpunit.xml --coverage-text --coverage-html ./var/tests-unit-coverage-html --coverage-clover ./var/tests-unit-clover-coverage.xml
 	$(DOCKER_RUN) test -n "$(COVERALLS_REPO_TOKEN)" && test -n "$(COVERALLS_RUN_LOCALLY)" && test -f ./var/tests-unit-clover-coverage.xml && vendor/bin/php-coveralls -v --coverage_clover ./build/logs/clover.xml --json_path ./var/tests-unit-clover-coverage-upload.json || true
 
 mutation-testing: ## Run mutation testing
-	$(DOCKER_RUN) vendor/bin/roave-infection-static-analysis-plugin --ansi --min-msi=100 --min-covered-msi=100 --threads=$(shell nproc) --ignore-msi-with-no-mutations || (cat ./var/infection.log && false)
+	$(DOCKER_RUN) vendor/bin/roave-infection-static-analysis-plugin --ansi --min-msi=100 --min-covered-msi=100 --threads=$(THREADS) --ignore-msi-with-no-mutations || (cat ./var/infection.log && false)
 
 composer-require-checker: ## Ensure we require every package used in this package directly
 	$(DOCKER_RUN) vendor/bin/composer-require-checker --ignore-parse-errors --ansi -vvv --config-file=./etc/qa/composer-require-checker.json