[electrum] make contrib/sign_packages support multi digits in version numbers
Summary: And exit with an error message when the version string is not detected, instead of producing a sha256_checksums.txt number without a version number.
Test Plan:
$ touch dist/ElectrumABC-1.1.1.tar.gz $ contrib/sign_packages Detected version number: 1.1.1 Checksum file: sha256_checksums-1.1.1.txt Password: Signature file: sha256_checksums-1.1.1.txt.sig $ rm dist/ElectrumABC-1.1.1.tar.gz $ touch dist/ElectrumABC-1.1.10.tar.gz $ contrib/sign_packages Detected version number: 1.1.10 Checksum file: sha256_checksums-1.1.10.txt Password: Signature file: sha256_checksums-1.1.10.txt.sig $ rm dist/ElectrumABC-1.1.10.tar.gz $ touch dist/ElectrumABC-1337.42.666.tar.gz $ contrib/sign_packages Detected version number: 1337.42.666 Checksum file: sha256_checksums-1337.42.666.txt Password: Signature file: sha256_checksums-1337.42.666.txt.sig $ rm dist/ElectrumABC-1337.42.666.tar.gz $ touch dist/ElectrumABC-1.1.1.1.tar.gz $ contrib/sign_packages Error: could not find release version number.
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D14978