all: Use fixed version number for java 6/7 signatures

This is important for stable builds, as if the signature changes the old source
may no longer validate.

auth/build.gradle

@@ -3,5 +3,5 @@ dependencies {
     compile project(':grpc-core'),
             libraries.google_auth_credentials
     testCompile libraries.oauth_client
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }

context/build.gradle

@@ -2,5 +2,5 @@ description = 'gRPC: Context'
 
 dependencies {
     testCompile project(':grpc-testing')
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }

core/build.gradle

@@ -7,7 +7,7 @@ dependencies {
             project(':grpc-context'),
             libraries.instrumentation_api
     testCompile project(':grpc-testing')
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }
 
 javadoc {

netty/build.gradle

@@ -8,7 +8,7 @@ dependencies {
     testCompile project(':grpc-core').sourceSets.test.output,
                 project(':grpc-testing')
     testRuntime libraries.netty_tcnative
-    signature "org.codehaus.mojo.signature:java17:+@signature"
+    signature "org.codehaus.mojo.signature:java17:1.0@signature"
 }
 
 [compileJava, compileTestJava].each() {

okhttp/build.gradle

@@ -8,7 +8,7 @@ dependencies {
     testCompile project(':grpc-core').sourceSets.test.output,
                 project(':grpc-testing'),
                 project(':grpc-netty')
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }
 
 project.sourceSets {

protobuf-lite/build.gradle

@@ -19,7 +19,7 @@ dependencies {
 
     testProtobuf libraries.protobuf
 
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }
 
 compileTestJava {

protobuf-nano/build.gradle

@@ -14,7 +14,7 @@ dependencies {
     compile project(':grpc-core'),
             libraries.protobuf_nano,
             libraries.guava
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }
 
 configureProtoCompilation()

protobuf/build.gradle

@@ -25,7 +25,7 @@ dependencies {
         exclude group: 'com.google.protobuf', module: 'protobuf-lite'
     }
 
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }
 
 configureProtoCompilation()

services/build.gradle

@@ -14,7 +14,7 @@ dependencies {
     compile project(':grpc-protobuf'),
             project(':grpc-stub')
     testCompile project(':grpc-testing')
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }
 
 configureProtoCompilation()

stub/build.gradle

@@ -3,7 +3,7 @@ dependencies {
     compile project(':grpc-core')
     testCompile libraries.truth,
     project(':grpc-testing')
-    signature "org.codehaus.mojo.signature:java16:+@signature"
+    signature "org.codehaus.mojo.signature:java16:1.1@signature"
 }
 
 javadoc.options.links "https://google.github.io/guava/releases/${guavaVersion}/api/docs/"