Update Spring Boot because of their issue 26627

spring-projects/spring-boot#26627

SpiNNaker-allocserv/pom.xml

@@ -27,7 +27,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 	<artifactId>SpiNNaker-allocserv</artifactId>
 	<packaging>war</packaging>
 	<properties>
-		<spring.boot.version>2.4.6</spring.boot.version>
+		<spring.boot.version>2.4.7</spring.boot.version>
 		<spring.version>5.3.7</spring.version>
 		<jackson.version>2.12.3</jackson.version>
 		<swagger.version>3.50.0</swagger.version>