Make GraphQL parameters strict following Absinthe 1.7 validating

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

test/graphql/resolvers/comment_test.exs

@@ -19,7 +19,7 @@ defmodule Mobilizon.GraphQL.Resolvers.CommentTest do
 
   describe "Comment Resolver" do
     @create_comment_mutation """
-    mutation CreateComment($text: String!, $eventId: ID, $inReplyToCommentId: ID) {
+    mutation CreateComment($text: String!, $eventId: ID!, $inReplyToCommentId: ID) {
       createComment(text: $text, eventId: $eventId, inReplyToCommentId: $inReplyToCommentId) {
         id,
         text,

test/graphql/resolvers/event_test.exs

@@ -75,7 +75,7 @@ defmodule Mobilizon.Web.Resolvers.EventTest do
     @create_event_mutation """
     mutation CreateEvent(
       $title: String!,
-      $description: String,
+      $description: String!,
       $begins_on: DateTime!,
       $ends_on: DateTime,
       $status: EventStatus,

test/graphql/resolvers/follower_test.exs

@@ -177,7 +177,7 @@ defmodule Mobilizon.Web.Resolvers.FollowerTest do
   end
 
   @update_follower_mutation """
-  mutation UpdateFollower($id: ID!, $approved: Boolean) {
+  mutation UpdateFollower($id: ID!, $approved: Boolean!) {
     updateFollower(id: $id, approved: $approved) {
       id
       approved

test/graphql/resolvers/post_test.exs

@@ -64,7 +64,7 @@ defmodule Mobilizon.GraphQL.Resolvers.PostTest do
   """
 
   @create_post """
-  mutation CreatePost($title: String!, $body: String, $attributedToId: ID!, $draft: Boolean) {
+  mutation CreatePost($title: String!, $body: String!, $attributedToId: ID!, $draft: Boolean) {
     createPost(title: $title, body: $body, attributedToId: $attributedToId, draft: $draft) {
       ...PostFragment
     }

test/graphql/resolvers/resource_test.exs

@@ -50,7 +50,7 @@ defmodule Mobilizon.GraphQL.Resolvers.ResourceTest do
   """
 
   @get_resource """
-  query GetResource($path: String, $username: String) {
+  query GetResource($path: String!, $username: String!) {
     resource(path: $path, username: $username) {
         id,
         title,