moved symfony finder to dev-dependency

[staabm]

Q	A
Bug fix?	No
New feature?	No
BC breaks?	No
Deprecations?	No
Fixed tickets	N/A

seems like the finder is not required for deployer itself, just for the build and phpcs.

Moved it to be a dev dependency so hopefully it wont be bundled with the deployer phar

[antonmedv]

The Travis CI build failed

[staabm]

The travis build doesnt like the noted issue number in the changelog.

Is it required to create a separate issue or could I just drop the number from the changelog?

[antonmedv]

Reference for a link [#1452] doesn't found in CHANGELOG.md
Add the next line to end of CHANGELOG.md file:
   [#1452]: https://github.com/deployphp/deployer/pull/1452

Take a look at the end of CHANGELOG.md

[staabm]

Ohh didnt read properly. Thx for the hint. Fixed.