fix: Update EKS module version to restrict TLS provider version

[bryantbiggs]

What does this PR do?

• Update EKS module version to restrict TLS provider version

Motivation

• More info can be found here fix: Pin TLS provider version to 3.x versions only terraform-aws-modules/terraform-aws-eks#2174 - the tl;dr is that a new v4.0 of the TLS provider was released yesterday and introduced a bug which is causing the tls_cert resource to fail. The change in v18.26.6 is just to restrict the provider from using v4.0 which is causing issues
• Closes Unexpected upstream (v18.26.5) breaking change #795

More

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Yes, I have added a new example under examples to support my PR
• Yes, I have created another PR for add-ons under add-ons repo (if applicable)
• Yes, I have updated the docs for this feature
• Yes, I ran pre-commit run -a with this PR

Note: Not all the PRs required examples and docs except a new pattern or add-on added.

For Moderators

• E2E Test successfully complete before merge?

Additional Notes