chore(show-spring-boot-version-diff.sh): fix "join: /dev/fd/62:21: is not sorted" error.

Filter out comments and compare properties only.

Fix #1213

Author: php-coder

src/main/scripts/show-spring-boot-version-diff.sh

@@ -21,8 +21,8 @@ printf "Comparing with Spring Boot %s (project vs spring versions)\\n\\n" "$SPRI
 # I know about useless cat below, but it's here for better readability.
 # shellcheck disable=SC2002
 join \
-	<(cat    "$PROJECT_POM" | awk -F'[<>]' -v OFS='\t' '$2~/\.version/{print $2, $3}' | sort) \
-	<(curl -s "$SPRING_POM" | awk -F'[<>]' -v OFS='\t' '$2~/\.version/{print $2, $3}' | sort) \
+	<(cat    "$PROJECT_POM" | awk -F'[<>]' -v OFS='\t' '$2~/\.version$/{print $2, $3}' | sort) \
+	<(curl -s "$SPRING_POM" | awk -F'[<>]' -v OFS='\t' '$2~/\.version$/{print $2, $3}' | sort) \
 	| awk '
 			{
 				if ($2 != $3){