Prepare 1.11.1 release (#137)

Prepare to publish for stable null safety (#105)

Async gap fixes (#96)

* Fix async gap handling. (backpublish)

Fix an issue where an async gap at the end of a stack trace would not
get parsed correctly due to the trailing newline being `trim()`'d.

Add tests to cover this case.

* Fixes async gap handling in Trace.parse and Chain.parse (backpublish)

Co-authored-by: Clement Skau <[email protected]>

Bump SDK constraints for pub (#95)

Use a 2.12.0 lower bound since pub does not understand allowed
experiments for earlier versions.

Use a 3.0.0 upper bound to avoid a warning in pub and to give some
flexibility in publishing for stable.

allow the 2.12 prerelease sdks (#87)

Allow earlier SDKs (#86)

This was bumped because it wasn't clear which SDKs it worked with,
however a comment on an earlier PR shows that it is compatible with
early SDKs.

Prepare to publish (#85)

Bump the min SDk to `2.11.0-0`. There were changes previously which
appear to depend on changes in the SDK that were not reflected in the
lower bound constraint, bump to a much more recent SDK for safety.

Avoid converting stacktrace to nullable and then null checking it. (#82)

The Dart implementation will soon be changed so that a declaration
such as `T? x = y`, where `y` has a non-nullable type, automatically
promotes `x` to a non-nullable type.  This will in turn cause a
warning if a non-nullable value is assigned to a nullable variable and
then null checked.

We're currently doing that in one place, and there's no need to, so
remove the unnecessary type conversion and null check.