Don't re-instantiate `defaultProvider()` in each interceptor

[ndowmon]

It seems that the awsV4Signature() function is loaded as an axios request interceptor in @lifeomic/alpha, which (I think) means that the function is invoked on each request. Since a new instance of defaultProvider() is instantiated at https://github.com/LifeOmic/alpha/blob/master/src/interceptors/aws-v4-signature.ts#L68, each lambda call is re-instantiating those credentials - meaning, re-invoking the ECS container metadata endpoint, if loading from ECS (or EC2).

It would be better if @lifeomic/alpha instantiated defaultProvider() just one time and re-used the same credential provider in the interceptor.

e.g.

+const DEFAULT_CREDENTIAL_PROVIDER = defaultProvider();
 const awsV4Signature: AlphaInterceptor = async (config) => {
   
   ...

   const {
-    credentials = defaultProvider(),
+    credentials = DEFAULT_CREDENTIAL_PROVIDER,

See https://github.com/JupiterOne/sdk/pull/930/files#r1270091324

---

Also, I'd recommend setting default retries in the defaultProvider(), like so:

-const DEFAULT_CREDENTIAL_PROVIDER = defaultProvider();
+const DEFAULT_CREDENTIAL_PROVIDER = defaultProvider({ maxRetries: 3 });

[swain]

@DavidTanner FYI