Add breaking changes and release 1.0.0.

CHANGELOG.md

Index: CHANGELOG.md
diff --git a/CHANGELOG.md b/CHANGELOG.md
index db7368619a7c212a39d1b59ea5eaa1d38f7c8eab..910d30ebcc05d9ed87d89a46bca3bc28d498aa22 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,16 @@
+## 1.0.0
+
+* **Breaking change**: `StringScanner.error()`'s `length` argument now defaults
+  to `0` rather than `1` when no match data is available.
+
+* **Breaking change**: `StringScanner.lastMatch` and related methods are now
+  reset when the scanner's position changes without producing a new match.
+
+**Note**: While the changes in `1.0.0` are user-visible, they're unlikely to
+actually break any code in practice. Unless you know that your package is
+incompatible with 0.1.x, consider using 0.1.5 as your lower bound rather
+than 1.0.0. For example, `string_scanner: ">=0.1.5 <2.0.0"`.
+
 ## 0.1.5
 
 * Add `new SpanScanner.within()`, which scans within a existing `FileSpan`.