Add repositories section to dependencies POM

Add a repositories section to the spring-boot-dependencies POM but
strip it out during a CI build. This allows snapshot and milestone
BOM imports to be used but doesn't pollute published POMs and doesn't
prevent a fresh checkout from building.

Fixes gh-1413

pom.xml

@@ -254,5 +254,34 @@
 				</plugins>
 			</build>
 		</profile>
+		<profile>
+			<id>ci</id>
+			<build>
+				<plugins>
+					<plugin>
+						<groupId>com.google.code.maven-replacer-plugin</groupId>
+						<artifactId>replacer</artifactId>
+						<executions>
+							<execution>
+								<id>remove-repo-samples</id>
+								<goals>
+									<goal>replace</goal>
+								</goals>
+								<configuration>
+									<includes>
+										<include>${basedir}/spring-boot-dependencies/pom.xml</include>
+									</includes>
+									<regexFlags>
+										<regexFlag>DOTALL</regexFlag>
+									</regexFlags>
+									<token>\n\t&lt;repositories&gt;.*&lt;/repositories&gt;</token>
+									<value></value>
+								</configuration>
+							</execution>
+						</executions>
+					</plugin>
+				</plugins>
+			</build>
+		</profile>
 	</profiles>
 </project>