use short license headers

I've been meaning to do this for a long time, and Sandro confirmed for
me that `reuse` also likes the short license headers.

Makefile

@@ -109,7 +109,7 @@ vendor-compat: FORCE
 
 force-license-headers: FORCE install-addlicense
 	@printf "\e[1;36m>> addlicense\e[0m\n"
-	echo -n $(patsubst $(shell awk '$$1 == "module" {print $$2}' go.mod)%,.%/*.go,$(shell go list ./...)) | xargs -d" " -I{} bash -c 'year="$$(rg -P "Copyright (....) SAP SE" -Nor "\$$1" {})"; awk -i inplace '"'"'{if (display) {print} else {!/^\/\*/ && !/^\*/ && !/^\$$/}}; /^package /{print;display=1}'"'"' {}; addlicense -c "SAP SE" -s -y "$$year" -- {}'
+	echo -n $(patsubst $(shell awk '$$1 == "module" {print $$2}' go.mod)%,.%/*.go,$(shell go list ./...)) | xargs -d" " -I{} bash -c 'year="$$(rg -P "Copyright (....) SAP SE" -Nor "\$$1" {})"; awk -i inplace '"'"'{if (display) {print} else {!/^\/\*/ && !/^\*/ && !/^\$$/}}; /^package /{print;display=1}'"'"' {}; addlicense -c "SAP SE" -s=only -y "$$year" -- {}'
 
 license-headers: FORCE install-addlicense
 	@printf "\e[1;36m>> addlicense\e[0m\n"

internal/makefile/makefile.go

@@ -416,7 +416,7 @@ endif
 			prerequisites: []string{"install-addlicense"},
 			recipe: []string{
 				`@printf "\e[1;36m>> addlicense\e[0m\n"`,
-				fmt.Sprintf(`echo -n %s | xargs -d" " -I{} bash -c 'year="$$(rg -P "Copyright (....) SAP SE" -Nor "\$$1" {})"; awk -i inplace '"'"'{if (display) {print} else {!/^\/\*/ && !/^\*/ && !/^\$$/}}; /^package /{print;display=1}'"'"' {}; addlicense -c "SAP SE" -s -y "$$year" %s {}'`, allSourceFilesExpr, ignoreOptionsStr),
+				fmt.Sprintf(`echo -n %s | xargs -d" " -I{} bash -c 'year="$$(rg -P "Copyright (....) SAP SE" -Nor "\$$1" {})"; awk -i inplace '"'"'{if (display) {print} else {!/^\/\*/ && !/^\*/ && !/^\$$/}}; /^package /{print;display=1}'"'"' {}; addlicense -c "SAP SE" -s=only -y "$$year" %s {}'`, allSourceFilesExpr, ignoreOptionsStr),
 			},
 		})