GH-501 - Make Micrometer Tracing a mandatory dependency of the observability module.

ModuleObservabilityAutoConfiguration strongly depends on said module and there's no way to make it optionally depending on that.

spring-modulith-observability/pom.xml

@@ -30,6 +30,11 @@
 			<version>${project.version}</version>
 		</dependency>
 
+		<dependency>
+			<groupId>io.micrometer</groupId>
+			<artifactId>micrometer-tracing</artifactId>
+		</dependency>
+
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-autoconfigure</artifactId>
@@ -47,7 +52,7 @@
 			<artifactId>spring-boot-starter-test</artifactId>
 			<scope>test</scope>
 		</dependency>
-		
+
 		<dependency>
 			<groupId>org.springframework.modulith</groupId>
 			<artifactId>spring-modulith-test</artifactId>
@@ -67,12 +72,6 @@
 			<optional>true</optional>
 		</dependency>
 
-		<dependency>
-			<groupId>io.micrometer</groupId>
-			<artifactId>micrometer-tracing</artifactId>
-			<optional>true</optional>
-		</dependency>
-
 		<!-- Testing -->
 
 		<dependency>