Merge instructions

To merge an tag <tag> (for example, OpenSSL_1_1_1i) from the upstream OpenSSL project (from remote upstream) into a branch <branch> (for example, OQS-OpenSSL_1_1_1-stable) of this project:

• Fetch the latest tags from the upstream project: git fetch --tags upstream
• Create a branch for the new tag: git checkout -b <tag_branch>
• Merge the tag: git merge <tag>
• Build and test the branch (python3 oqs-template/generate.py && make generate_crypto_objects && make test && LD_LIBRARY_PATH=. python3 -m pytest oqs-test/test_tls_full.py)
• After all tests pass, push the branch <tag_branch> and pull into <branch>