chore: Use pip3 explicitly to install yamllint

Distribution stends to skip unversionned pip for compatibility issues.
Also, yamllint requires Python 3.8+.

Signed-off-by: Étienne BERSAC <etienne.bersac@dalibo.com>

Makefile

@@ -68,7 +68,7 @@ bin/golangci-lint:
 
 .PHONY: yamllint
 yamllint:
-	pip install --user yamllint
+	pip3 install --user yamllint
 
 # Add custom targets here
 -include custom.mk