Fix backend bootstrap error

Signed-off-by: Guillaume Lours <guillaume.lours@docker.com>

sparkjava-mysql/backend/pom.xml

@@ -40,7 +40,7 @@
         <dependency>
             <groupId>com.sparkjava</groupId>
             <artifactId>spark-core</artifactId>
-            <version>2.8.0</version>
+            <version>2.9.2</version>
         </dependency>
 
         <dependency>

sparkjava-mysql/backend/src/main/java/App.java

@@ -64,7 +64,7 @@ public class App {
     private static Connection connect() throws Exception {
         for (int i = 0; i < 60; i++) {
             try {
-                return DriverManager.getConnection("jdbc:mysql://db/example?useSSL=false", "root", Files.lines(Paths.get("/run/secrets/db-password")).findFirst().get());
+                return DriverManager.getConnection("jdbc:mysql://db/example?allowPublicKeyRetrieval=true&useSSL=false", "root", Files.lines(Paths.get("/run/secrets/db-password")).findFirst().get());
             } catch (CommunicationsException ex) {
                 Thread.sleep(1000L);
                 continue;

sparkjava/sparkjava/pom.xml

@@ -40,7 +40,7 @@
         <dependency>
             <groupId>com.sparkjava</groupId>
             <artifactId>spark-core</artifactId>
-            <version>2.8.0</version>
+            <version>2.9.2</version>
         </dependency>
 
     </dependencies>