CI: Make cross-compiled release artifacts statically linked to OpenSSL

We preferred dynamic linking because that makes it easy for end users to
upgrade OpenSSL (potentially with security fixes) without reinstalling
the app.

When cross-compiling, however, we use a container based on Ubuntu 20.04,
which does not have `libssl3` package, making the release artifact
depend on OpenSSL 1.1.1, which will reach EOL at 2013-09-11
(<https://www.openssl.org/blog/blog/2023/03/28/1.1.1-EOL/>). See also
<cross-rs/cross#973> for current status of the
container image.

This commit aims at working around the problem by statically linking
against OpenSSL when cross compiling, so that the end user does not
need to install OpenSSL 1.1.1.

.github/workflows/cicd.yml

@@ -121,8 +121,10 @@ jobs:
  - os: ubuntu-latest
  - target: aarch64-unknown-linux-gnu
  use_cross: true
+ features: [openssl-vendored]
  - target: armv7-unknown-linux-gnueabihf
  use_cross: true
+ features: [openssl-vendored]
  - target: aarch64-apple-darwin
  os: macos-latest
  - target: x86_64-apple-darwin