fix: escape parenthesis in Makefile error message that broke CI-builds

The $(error ...) call on line 81 contained a literal ')' in
"(expected format: X.Y.Z)" which make interprets as the closing
delimiter of the $(error) function. This caused all docker-compose
build targets (ubuntu22-dbg, ubuntu22-tap, etc.) to fail with
"unterminated call to function 'error': missing ')'".

This was the root cause of CI-builds failing since Release 3.0.8.

Makefile

@@ -78,7 +78,7 @@ CURVER := $(shell echo "$(GIT_VERSION)" | sed -nE 's/^([0-9]+\.[0-9]+\.[0-9]+).*
 CURVER_CHECK := $(shell echo "$(CURVER)" | grep -cE '^[0-9]+\.[0-9]+\.[0-9]+$$')
 
 ifeq ($(CURVER_CHECK),0)
-    $(error CURVER "$(CURVER)" derived from GIT_VERSION "$(GIT_VERSION)" does not have 3 numbers separated by dots (expected format: X.Y.Z)
+    $(error CURVER "$(CURVER)" derived from GIT_VERSION "$(GIT_VERSION)" does not have 3 numbers separated by dots. Expected format: X.Y.Z
 endif
 
 export CURVER