Prepare for v1.18.0 (#805)

Below are the draft notes for the release:

----

# v1.18.0

## What's Changed
### Enhancements
* Add `package_suffix` option to `protoc-gen-connect-go` to allow
specifying the output directory of generated code by @bufdev and
@emcfarlane in #803
* Change stream client closures to be non-blocking by @emcfarlane in
#791
### Other changes
* Fix comment typo spelling of optimize by @yoshihiro-shu in
#786
* Remove reader allocation for compressors pools by @emcfarlane in
#792

## New Contributors
* @yoshihiro-shu made their first contribution in
#786

**Full Changelog**:
v1.17.0...v1.18.0

Signed-off-by: Edward McFarlane <[email protected]>

connect.go

@@ -33,7 +33,7 @@ import (
 )
 
 // Version is the semantic version of the connect module.
-const Version = "1.18.0-dev"
+const Version = "1.18.0"
 
 // These constants are used in compile-time handshakes with connect's generated
 // code.