GitHub GraphQL API Filter on custom text field in Project V2

We are using GitHub Projects (Beta). I created a custom text field called oma-project. I want to use the API to filter on this field, e.g., oma-project: "P0001". This should return all issues with this value in the custom field.

Looking at the Projects (beta) docs, I can list the first n issues but I don’t know how I can pass a filter based on the value of the custom field.

This is as far as I have gotten.

{
  node(id: "nodeid") {
    ... on ProjectV2 {
      items(first: 2) {
        nodes {
          fieldValues(first: 8) {
            nodes {
              ... on ProjectV2ItemFieldTextValue {
                text
                field {
                  ... on ProjectV2FieldCommon {
                    name
                  }
                }
              }
            }
          }
          content {
            ... on Issue {
              id
              title
            }
          }
        }
      }
    }
  }
}

returns:

{
  "data": {
    "node": {
      "items": {
        "nodes": [
          {
            "fieldValues": {
              "nodes": [
                {},
                {},
                {},
                {
                  "text": "Retrieve Notes via OData",
                  "field": {
                    "name": "Title"
                  }
                },
                {},
                {
                  "text": "P9999",
                  "field": {
                    "name": "OMA Project"
                  }
                }
              ]
            },
            "content": {
              "id": "I_kwDOFT-pvM5AZNLm",
              "title": "Retrieve Notes via OData"
            }
          },
          {
            "fieldValues": {
              "nodes": [
                {},
                {},
                {
                  "text": "Capex Approval Type",
                  "field": {
                    "name": "Title"
                  }
                },
                {},
                {},
                {
                  "text": "P0708",
                  "field": {
                    "name": "OMA Project"
                  }
                }
              ]
            },
            "content": {
              "id": "I_kwDOFT-pvM5K85HZ",
              "title": "Capex Approval Type"
            }
          }
        ]
      }
    }
  }
}