TypeScript < 4 not supported

[johnsickels]

We are seeing this on tsc or flagpole build with typescript version 3.8.3

node_modules/flagpole/node_modules/ajv/dist/types/json-schema.d.ts:1:92 - error TS1005: '?' expected.

1 declare type StrictNullChecksWrapper<Name extends string, Type> = undefined extends null ? `strictNullChecks must be true in tsconfig to use ${Name}` : Type;
                                                                                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

node_modules/flagpole/node_modules/ajv/dist/types/json-schema.d.ts:1:151 - error TS1005: ';' expected.

1 declare type StrictNullChecksWrapper<Name extends string, Type> = undefined extends null ? `strictNullChecks must be true in tsconfig to use ${Name}` : Type;

ajv-validator/ajv#1650

[FloDanny]

Our cloud build has this error:
Step #9 - "Run UI Tests": node_modules/flagpole/node_modules/ajv/dist/types/json-schema.d.ts(1,92): error TS1005: '?' expected. Step #9 - "Run UI Tests": node_modules/flagpole/node_modules/ajv/dist/types/json-schema.d.ts(1,151): error TS1005: ';' expected.

[johnsickels]

The straw that broke the camel's back https://github.com/ajv-validator/ajv/releases/tag/v8.3.0

[johnsickels]

Finished Step #2 - "Install"
2021/09/12 13:23:35 Step Step #2 - "Install" finished
Starting Step #3 - "Run UI Tests"
Step #3 - "Run UI Tests": Already have image: gcr.io/flosports-174016/scorecard:FX-1786-local-cb-script
Step #3 - "Run UI Tests": 
Step #3 - "Run UI Tests": > [email protected] test-ui-stag /workspace
Step #3 - "Run UI Tests": > tsc -p ./src/tsconfig.e2e.json && flagpole run --all -e stag -o xml
Step #3 - "Run UI Tests": 
Step #3 - "Run UI Tests": node_modules/flagpole/node_modules/ajv/dist/types/json-schema.d.ts(1,92): error TS1005: '?' expected.
Step #3 - "Run UI Tests": node_modules/flagpole/node_modules/ajv/dist/types/json-schema.d.ts(1,151): error TS1005: ';' expected.
Step #3 - "Run UI Tests": npm ERR! code ELIFECYCLE
Step #3 - "Run UI Tests": npm ERR! errno 2
Step #3 - "Run UI Tests": npm ERR! [email protected] test-ui-stag: `tsc -p ./src/tsconfig.e2e.json && flagpole run --all -e stag -o xml`
Step #3 - "Run UI Tests": npm ERR! Exit status 2

node v12
typescript v3.8.3
flagpole v2.6.5

[johnsickels]

ajv-validator/ajv#1687