Bump org.springframework.boot:spring-boot-starter-parent in /backend

Bumps [org.springframework.boot:spring-boot-starter-parent](https://github.com/spring-projects/spring-boot) from 3.1.3 to 3.1.5.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.1.3...v3.1.5)

---
updated-dependencies:
- dependency-name: org.springframework.boot:spring-boot-starter-parent
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

backend/auth-service/pom.xml

@@ -9,7 +9,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>3.1.3</version>
+        <version>3.1.5</version>
         <relativePath />
     </parent>
 

backend/device-service/pom.xml

@@ -9,7 +9,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>3.1.3</version>
+		<version>3.1.5</version>
 		<relativePath />
 	</parent>
 

backend/discovery-service/pom.xml

@@ -9,7 +9,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>3.1.3</version>
+        <version>3.1.5</version>
         <relativePath />
     </parent>
 

backend/gateway-service/pom.xml

@@ -6,7 +6,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>3.1.3</version>
+		<version>3.1.5</version>
 		<relativePath />
 	</parent>
 

backend/measurement-service/pom.xml

@@ -9,7 +9,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>3.1.3</version>
+		<version>3.1.5</version>
 		<relativePath />
 	</parent>
 

backend/token-service/pom.xml

@@ -9,7 +9,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>3.1.3</version>
+		<version>3.1.5</version>
 		<relativePath />
 	</parent>
 

backend/user-service/pom.xml

@@ -9,7 +9,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>3.1.3</version>
+		<version>3.1.5</version>
 		<relativePath />
 	</parent>