Getting "TSError: ⨯ Unable to compile TypeScript" on startup

[dwking2000]

fresh pull from git
note - I do not see a directory dotenv/config

then:
yarn install --ignore-engines
yarn start

console shows:
yarn run v1.7.0
$ nodemon -e ts,graphql -x ts-node -r dotenv/config src/index.ts
[nodemon] 1.17.5
[nodemon] to restart at any time, enter rs
[nodemon] watching: .
[nodemon] starting ts-node -r dotenv/config src/index.ts

then I get the following error:

/git/cleargraph/node_modules/ts-node/src/index.ts:253
return new TSError(diagnosticText, diagnosticCodes)
^
TSError: ⨯ Unable to compile TypeScript:
src/index.ts(7,41): error TS2345: Argument of type '{ context: (req: any) => Context; resolvers: typeof import("/git/cleargraph/src/re...' is not assignable to parameter of type 'Props'.
Types of property 'resolvers' are incompatible.
Type 'typeof import("/git/cleargraph/src/resolvers/index")' is not assignable to type 'IResolvers'.
Property 'BigNumber' is incompatible with index signature.
Type 'GraphQLScalarType' is not assignable to type '(() => any) | IResolverObject | GraphQLScalarType'.
Type 'import("/git/cleargraph/node_modules/@types/graphql/type/definition").GraphQLScala...' is not assignable to type 'import("/git/cleargraph/node_modules/graphql-yoga/node_modules/@types/graphql/type...'.
Property 'extensionASTNodes' is missing in type 'GraphQLScalarType'.