add a changelog file, prepping for v0.1.1

The v0.1.0 notes are copied from the GitHub release.

CHANGELOG.md

@@ -0,0 +1,35 @@
+# Changelog
+
+## [0.1.1] - 2021-03-11
+
+This bugfix release backports fixes for a few issues:
+
+* Keep leading empty lines in func bodies if they help readability
+
+* Avoid breaking comment alignment on empty field lists
+
+* Add support for `//go-sumtype:` directives
+
+## [0.1.0] - 2021-01-05
+
+This is gofumpt's first release, based on Go 1.15.x. It solidifies the features
+which have worked well for over a year.
+
+This release will be the last to include `gofumports`, the fork of `goimports`
+which applies `gofumpt`'s rules on top of updating the Go import lines. Users
+who were relying on `goimports` in their editors or IDEs to apply both `gofumpt`
+and `goimports` in a single step should switch to gopls, the official Go
+language server. It is supported by many popular editors such as VS Code and
+Vim, and already bundles gofumpt support. Instructions are available [in the
+README](https://github.com/mvdan/gofumpt).
+
+`gofumports` also added maintenance work and potential confusion to end users.
+In the future, there will only be one way to use `gofumpt` from the command
+line. We also have a [Go API](https://pkg.go.dev/mvdan.cc/gofumpt/format) for
+those building programs with gofumpt.
+
+Finally, this release adds the `-version` flag, to print the tool's own version.
+The flag will work for "master" builds too.
+
+[0.1.1]: https://github.com/mvdan/gofumpt/releases/tag/v0.1.1
+[0.1.0]: https://github.com/mvdan/gofumpt/releases/tag/v0.1.0