GraphQL: Make runner fields nullable

Some fields are nullable in the database schema
but were not marked as such in the GraphQL type

app/graphql/types/ci/runner_type.rb

@@ -25,17 +25,17 @@ module Types
             description: 'Indicates the runner is allowed to receive jobs.'
       field :status, ::Types::Ci::RunnerStatusEnum, null: false,
             description: 'Status of the runner.'
-      field :version, GraphQL::STRING_TYPE, null: false,
+      field :version, GraphQL::STRING_TYPE, null: true,
             description: 'Version of the runner.'
       field :short_sha, GraphQL::STRING_TYPE, null: true,
             description: %q(First eight characters of the runner's token used to authenticate new job requests. Used as the runner's unique ID.)
-      field :revision, GraphQL::STRING_TYPE, null: false,
+      field :revision, GraphQL::STRING_TYPE, null: true,
             description: 'Revision of the runner.'
       field :locked, GraphQL::BOOLEAN_TYPE, null: true,
             description: 'Indicates the runner is locked.'
       field :run_untagged, GraphQL::BOOLEAN_TYPE, null: false,
             description: 'Indicates the runner is able to run untagged jobs.'
-      field :ip_address, GraphQL::STRING_TYPE, null: false,
+      field :ip_address, GraphQL::STRING_TYPE, null: true,
             description: 'IP address of the runner.'
       field :runner_type, ::Types::Ci::RunnerTypeEnum, null: false,
             description: 'Type of the runner.'

doc/api/graphql/reference/index.md

@@ -7780,20 +7780,20 @@ Represents the total number of issues and their weights for a particular day.
 | <a id="cirunnercontactedat"></a>`contactedAt` | [`Time`](#time) | Last contact from the runner. |
 | <a id="cirunnerdescription"></a>`description` | [`String`](#string) | Description of the runner. |
 | <a id="cirunnerid"></a>`id` | [`CiRunnerID!`](#cirunnerid) | ID of the runner. |
-| <a id="cirunneripaddress"></a>`ipAddress` | [`String!`](#string) | IP address of the runner. |
+| <a id="cirunneripaddress"></a>`ipAddress` | [`String`](#string) | IP address of the runner. |
 | <a id="cirunnerjobcount"></a>`jobCount` | [`Int`](#int) | Number of jobs processed by the runner (limited to 1000, plus one to indicate that more items exist). |
 | <a id="cirunnerlocked"></a>`locked` | [`Boolean`](#boolean) | Indicates the runner is locked. |
 | <a id="cirunnermaximumtimeout"></a>`maximumTimeout` | [`Int`](#int) | Maximum timeout (in seconds) for jobs processed by the runner. |
 | <a id="cirunnerprivateprojectsminutescostfactor"></a>`privateProjectsMinutesCostFactor` | [`Float`](#float) | Private projects' "minutes cost factor" associated with the runner (GitLab.com only). |
 | <a id="cirunnerprojectcount"></a>`projectCount` | [`Int`](#int) | Number of projects that the runner is associated with. |
 | <a id="cirunnerpublicprojectsminutescostfactor"></a>`publicProjectsMinutesCostFactor` | [`Float`](#float) | Public projects' "minutes cost factor" associated with the runner (GitLab.com only). |
-| <a id="cirunnerrevision"></a>`revision` | [`String!`](#string) | Revision of the runner. |
+| <a id="cirunnerrevision"></a>`revision` | [`String`](#string) | Revision of the runner. |
 | <a id="cirunnerrununtagged"></a>`runUntagged` | [`Boolean!`](#boolean) | Indicates the runner is able to run untagged jobs. |
 | <a id="cirunnerrunnertype"></a>`runnerType` | [`CiRunnerType!`](#cirunnertype) | Type of the runner. |
 | <a id="cirunnershortsha"></a>`shortSha` | [`String`](#string) | First eight characters of the runner's token used to authenticate new job requests. Used as the runner's unique ID. |
 | <a id="cirunnerstatus"></a>`status` | [`CiRunnerStatus!`](#cirunnerstatus) | Status of the runner. |
 | <a id="cirunnertaglist"></a>`tagList` | [`[String!]`](#string) | Tags associated with the runner. |
-| <a id="cirunnerversion"></a>`version` | [`String!`](#string) | Version of the runner. |
+| <a id="cirunnerversion"></a>`version` | [`String`](#string) | Version of the runner. |
 
 ### `CiStage`