Roll Observatory packages and add a roll script

packages/source_maps/CHANGELOG.md

+## 0.10.1
+
+* Add a `mapUrl` named argument to `parse` and `parseJson`. This argument is
+  used to resolve source URLs for source spans.
+
+## 0.10.0+2
+
+* Fix analyzer error (FileSpan has a new field since `source_span` 1.1.1)
+
+## 0.10.0+1
+
+* Remove an unnecessary warning printed when the "file" field is missing from a
+  Json formatted source map. This field is optional and its absence is not
+  unusual.
+
+## 0.10.0
+
+* Remove the `Span`, `Location` and `SourceFile` classes. Use the
+  corresponding `source_span` classes instead.
+
+## 0.9.4
+
+* Update `SpanFormatException` with `source` and `offset`.
+
+* All methods that take `Span`s, `Location`s, and `SourceFile`s as inputs now
+  also accept the corresponding `source_span` classes as well. Using the old
+  classes is now deprecated and will be unsupported in version 0.10.0.
+
+## 0.9.3
+
+* Support writing SingleMapping objects to source map version 3 format.
+* Support the `sourceRoot` field in the SingleMapping class.
+* Support updating the `targetUrl` field in the SingleMapping class.
+
+## 0.9.2+2
+
+* Fix a bug in `FixedSpan.getLocationMessage`.
+
+## 0.9.2+1
+
+* Minor readability improvements to `FixedSpan.getLocationMessage` and
+  `SpanException.toString`.
+
+## 0.9.2
+
+* Add `SpanException` and `SpanFormatException` classes.
+
+## 0.9.1
+
+* Support unmapped areas in source maps.
+
+* Increase the readability of location messages.