format code with gofumpt

gofumpt (https://github.com/mvdan/gofumpt) provides a supserset of `gofmt` / `go fmt`,
and addresses various formatting issues that linters may be checking for.

We can consider enabling the `gofumpt` linter to verify the formatting in CI, although
not every developer may have it installed, so for now this runs it once to get formatting
in shape.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

registry/storage/filereader_test.go

@@ -61,7 +61,6 @@ func TestFileReaderSeek(t *testing.T) {
 	}
 
 	fr, err := newFileReader(ctx, driver, path, int64(len(content)))
-
 	if err != nil {
 		t.Fatalf("unexpected error creating file reader: %v", err)
 	}