:tada: Add build date

Date of the compilation.

makefile

@@ -22,7 +22,9 @@ DIST_INC_FILES := $(INCLUDED_FILES:src/%=$(DIST_DIR)/%)
 DIST_EMB_FILES := $(EMBEDDED_FILES:src/%=$(DIST_DIR)/%)
 DIST_FILES := $(DIST_GEN_FILES) $(DIST_INC_FILES) $(DIST_DWN_FILES) $(DIST_EMB_FILES) $(DIST_DIR)/favicon.ico
 
-PANDOC_GEN := pandoc --template src/templates/main.html --metadata-file src/meta.yml --wrap=none
+BUILD_DATE := $(shell date "+%F")
+
+PANDOC_GEN := pandoc --template src/templates/main.html --metadata-file src/meta.yml --metadata=build-date:$(BUILD_DATE) --wrap=none
 LIST_GEN := yq eval-all '{"data": ., "target": {"content": filename | sub("meta.yml", "html") | sub(".*/", ""), "dir": filename | sub("$(DIR_OF_PROJECTS)/", "") | sub("/[^/]*.yml", "")}} as $$item ireduce ([]; . + $$item) | {"list": .}'
 
 # Functions