[openssl/openssl] 39ea31: Update workflow to use GITHUB_WORKSPACE

[Neil Horman]

  Branch: refs/heads/openssl-3.2
  Home:   https://github.com/openssl/openssl
  Commit: 39ea3155be08b5f3d5ef25d10c63bd5404efd094
      https://github.com/openssl/openssl/commit/39ea3155be08b5f3d5ef25d10c63bd5404efd094
  Author: Neil Horman <nhorman at openssl.org>
  Date:   2024-01-05 (Fri, 05 Jan 2024)

  Changed paths:
    M .github/workflows/interop-tests.yml

  Log Message:
  -----------
  Update workflow to use GITHUB_WORKSPACE

It was pointed out the GITHUB_WORKSPACE points to the container path of
the workspace, so we can use it instead of hardcoding the
__w/openssl/openssl path

Reviewed-by: Matt Caswell <matt at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22726)

(cherry picked from commit 638ad52ae53ece2e870984430493e454f75d048a)