Seems that additinal refresh of go.sum files is needed during the
release process after editing the versions of modules.
Discovered the problem while I was testing whether etcdutl is
properly included in the target binaries using:
```
DRY_RUN=true REPOSITORY=\`pwd\` BRANCH='branch-with-etcdutl' ./scripts/release 3.5.0-foobar.2
```
- making sure the DRY_RUN mode can finish e2e, so e.g. commits to
local copy of repository are OK in dry-run (while git pushes are NOT).
- better interaction with ./test_lib.sh script.
- more consistent logging
- bringing back s390x architecture that on go 1.14.3 seems to work as
expected.
Changes:
- signing tags.
- allows to override BRANCH and REPOSITORY using env variables.
Tested by a release in my private fork:
BRANCH="20201126-ptabor-release" REPOSITORY="git@github.com:ptabor/etcd.git" ./scripts/release 3.5.0-alpha.20
Examplar invocations:
Edit go.mod files such that all etcd modules are pointing on given version:
```
% DRY_RUN=false TARGET_VERSION="v3.5.13" ./scripts/release_mod.sh update_versions
```
Tag latest commit with current version number for all the modules and push upstream:
```
% DRY_RUN=true REMOTE_REPO="origin" ./scripts/release_mod.sh push_mod_tags
```
