Added the option "inProgress" to the contract

without this change we can't have a contract that will generate a stub but not a test. Of course that's for a reason since it's overriding the very essence of contract test.
with this change we assume that the users know what they're doing and that they will use this flag rarerly. Cause it means that you can have a false positive.

related to gh-881

specs/spring-cloud-contract-spec-java/src/main/java/org/springframework/cloud/contract/spec/Contract.java

@@ -89,6 +89,12 @@ public class Contract {
 	 */
 	private boolean ignored;
 
+	/**
+	 * Whether the contract is in progress. It's not ignored, but the feature is not yet
+	 * finished. Used together with the {@code generateStubs} option.
+	 */
+	private boolean inProgress;
+
 	public Contract() {
 
 	}
@@ -259,6 +265,17 @@ public class Contract {
 		this.ignored = true;
 	}
 
+	/**
+	 * Whether the contract is in progress or not.
+	 */
+	public void inProgress() {
+		this.inProgress = true;
+	}
+
+	public boolean isInProgress() {
+		return this.inProgress;
+	}
+
 	public Integer getPriority() {
 		return priority;
 	}
@@ -335,6 +352,10 @@ public class Contract {
 		this.ignored = ignored;
 	}
 
+	public void setInProgress(boolean inProgress) {
+		this.inProgress = inProgress;
+	}
+
 	@Override
 	public boolean equals(Object o) {
 		if (this == o) {