Readable-stream dependency is not fixed to Streams2

[hvrauhal]

Readable-stream is versioned so that ~1.0.0 is Streams2, ~1.1.0 is Streams3.

The prefix for readable-stream dependency has changed to ^ in 60cef0132ef2c251657cbc67d24c37a70e450ca4 which allows tar-stream to depend on the 1.1.x Streams3 versions of readable-stream.

[hvrauhal]

At the moment this causes readable-stream 1.0.26 to be installed at npm install and upgraded to 1.1.13 when running npm update with npm 1.4.21:

➜  sampleproject  npm --version
1.4.21
➜  sampleproject  cat package.json
{
  "name": "sampleproject",
  "version": "0.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {}
}
➜  sampleproject  npm install --save tar-stream
npm WARN package.json sampleproject@0.0.0 No description
npm WARN package.json sampleproject@0.0.0 No repository field.
npm WARN package.json sampleproject@0.0.0 No README data
tar-stream@1.1.2 node_modules/tar-stream
├── xtend@4.0.0
├── bl@0.9.4
├── readable-stream@1.0.33 (isarray@0.0.1, inherits@2.0.1, string_decoder@0.10.31, core-util-is@1.0.1)
└── end-of-stream@1.1.0 (once@1.3.1)
➜  sampleproject  npm update
npm WARN unmet dependency /Users/rauhahe/o/sampleproject/node_modules/tar-stream/node_modules/bl requires readable-stream@'~1.0.26' but will load
npm WARN unmet dependency /Users/rauhahe/o/sampleproject/node_modules/tar-stream/node_modules/readable-stream,
npm WARN unmet dependency which is version 1.1.13
readable-stream@1.1.13 node_modules/tar-stream/node_modules/readable-stream
├── isarray@0.0.1
├── inherits@2.0.1
├── string_decoder@0.10.31
└── core-util-is@1.0.1
➜  sampleproject  npm ls
npm WARN unmet dependency /Users/rauhahe/o/sampleproject/node_modules/tar-stream/node_modules/bl requires readable-stream@'~1.0.26' but will load
npm WARN unmet dependency /Users/rauhahe/o/sampleproject/node_modules/tar-stream/node_modules/readable-stream,
npm WARN unmet dependency which is version 1.1.13
sampleproject@0.0.0 /Users/rauhahe/o/sampleproject
└─┬ tar-stream@1.1.2
  ├── bl@0.9.4
  ├─┬ end-of-stream@1.1.0
  │ └─┬ once@1.3.1
  │   └── wrappy@1.0.1
  ├─┬ readable-stream@1.1.13 invalid
  │ ├── core-util-is@1.0.1
  │ ├── inherits@2.0.1
  │ ├── isarray@0.0.1
  │ └── string_decoder@0.10.31
  └── xtend@4.0.0

npm ERR! invalid: readable-stream@1.1.13 /Users/rauhahe/o/sampleproject/node_modules/tar-stream/node_modules/readable-stream
npm ERR! not ok code 0
➜  sampleproject

[mafintosh]

Could you send me a PR that pins it to the patch version?