chore!: update functions-framework-api dependency to 2.0.0 (#365)

Author: akerekes

invoker/conformance/pom.xml

@@ -28,7 +28,7 @@
     <dependency>
       <groupId>com.google.cloud.functions</groupId>
       <artifactId>functions-framework-api</artifactId>
-      <version>1.1.4</version>
+      <version>2.0.0</version>
     </dependency>
     <dependency>
       <groupId>com.google.code.gson</groupId>

invoker/core/pom.xml

@@ -46,7 +46,7 @@
     <dependency>
       <groupId>com.google.cloud.functions</groupId>
       <artifactId>functions-framework-api</artifactId>
-      <version>1.1.4</version>
+      <version>2.0.0</version>
     </dependency>
     <dependency>
       <groupId>io.cloudevents</groupId>

invoker/pom.xml

@@ -65,7 +65,7 @@
       <dependency>
         <groupId>com.google.cloud.functions</groupId>
         <artifactId>functions-framework-api</artifactId>
-        <version>1.1.4</version>
+        <version>2.0.0</version>
       </dependency>
     </dependencies>
   </dependencyManagement>

invoker/testfunction/pom.xml

@@ -20,7 +20,7 @@
     <dependency>
       <groupId>com.google.cloud.functions</groupId>
       <artifactId>functions-framework-api</artifactId>
-      <version>1.1.4</version>
+      <version>2.0.0</version>
     </dependency>
     <dependency>
       <!-- We don't actually use this; we just check that its classes can be