Compatibility check if Spring Boot version is unknown

It is better not to fail the compatibility check if the Spring Boot version is unknown.

spring-cloud-commons/src/main/java/org/springframework/cloud/configuration/SpringBootVersionVerifier.java

@@ -87,8 +87,11 @@ class SpringBootVersionVerifier implements CompatibilityVerifier {
 		if (log.isDebugEnabled()) {
 			log.debug("Version found in Boot manifest [" + version + "]");
 		}
-		return StringUtils.hasText(version)
-				&& version.startsWith(stripWildCardFromVersion(s));
+		if (!StringUtils.hasText(version)) {
+			log.info("Cannot check Boot version");
+			return true;
+		}
+		return version.startsWith(stripWildCardFromVersion(s));
 	}
 
 	String getVersionFromManifest() {

spring-cloud-commons/src/test/java/org/springframework/cloud/configuration/SpringBootDependencyTests.java

@@ -132,7 +132,7 @@ public class SpringBootDependencyTests {
 				acceptedVersions) {
 			@Override
 			String getVersionFromManifest() {
-				return "";
+				return "2.1";
 			}
 		};
 		versionVerifier.ACCEPTED_VERSIONS.clear();
@@ -207,7 +207,7 @@ public class SpringBootDependencyTests {
 				acceptedVersions) {
 			@Override
 			String getVersionFromManifest() {
-				return "";
+				return "2.0";
 			}
 		};
 		versionVerifier.ACCEPTED_VERSIONS.remove("2.1");