update CHANGELOG.md for v0.3.0

CHANGELOG.md

@@ -1,4 +1,32 @@
 # Changelog
+## [v0.3.0](https://github.com/itchyny/gojq/compare/v0.2.0..v0.3.0) (2019-06-05)
+
+* implement `reduce`, `foreach`, `label`, `break` syntax
+* improve binding variable syntax to bind to an object or an array
+* implement string interpolation
+* implement object index by string (`."example"`)
+* implement various functions (`add`, `flatten`, `min`, `min_by`, `max`,
+  `max_by`, `sort`, `sort_by`, `group_by`, `unique`, `unique_by`, `tostring`,
+  `indices`, `index`, `rindex`, `walk`, `transpose`, `first`, `last`, `nth`,
+  `limit`, `all`, `any`, `isempty`, `error`, `builtins`, `env`)
+* implement math functions (`sin`, `cos`, `tan`, `asin`, `acos`, `atan`,
+  `sinh`, `cosh`, `tanh`, `asinh`, `acosh`, `atanh`, `floor`, `round`,
+  `rint`, `ceil`, `trunc`, `fabs`, `sqrt`, `cbrt`, `exp`, `exp10`, `exp2`,
+  `expm1`, `frexp`, `modf`, `log`, `log10`, `log1p`, `log2`, `logb`,
+  `gamma`, `tgamma`, `lgamma`, `erf`, `erfc`, `j0`, `j1`, `y0`, `y1`,
+  `atan2/2`, `copysign/2`, `drem/2`, `fdim/2`, `fmax/2`, `fmin/2`, `fmod/2`,
+  `hypot/2`, `jn/2`, `ldexp/2`, `nextafter/2`, `nexttoward/2`, `remainder/2`,
+  `scalb/2`, `scalbln/2`, `pow/2`, `yn/2`, `fma/3`)
+* support object construction with variables
+* support indexing against strings
+* fix function evaluation for recursive call
+* fix error handling of `//` operator
+* fix string representation of NaN and Inf
+* implement `-R` flag for reading input as raw strings
+* implement `-c` flag for compact output
+* implement `-n` flag for using null as input value
+* implement `-r` flag for outputting raw string
+* implement `-s` flag for reading all inputs into an array
 
 ## [v0.2.0](https://github.com/itchyny/gojq/compare/v0.1.0..v0.2.0) (2019-05-06)