fix: graalvm image terraform install

[burkedavison]

Terraform install stopped working from default yum repo.

From https://www.hashicorp.com/official-packaging-guide :

Add the HashiCorp repo
Note: The provided repository configuration covers the supported distributions listed above. If you are using a variant not listed, you are encouraged to modify the repository configuration to suit your needs. For example, users of RHEL 7Server or RHEL 8.3 can change the baseurl to use 7 or 8 respectively in place of the $releasever variable.

[lqiu96]

Due to a CI issue in #793

Step #0 - "graalvm-a-build": Step 8/10 : RUN yum -y install terraform
Step #0 - "graalvm-a-build":  ---> Running in 6dc0b691c50a
Step #0 - "graalvm-a-build": Loaded plugins: ovl
Step #0 - "graalvm-a-build": No package terraform available.
Step #0 - "graalvm-a-build": Error: Nothing to do
Step #0 - "graalvm-a-build": The command '/bin/sh -c yum -y install terraform' returned a non-zero code: 1