Update losses implementation (#11667)

* Update README.md

Minor rewording

* Update ISSUE_TEMPLATE.md

Made explicit HTTPS call

* Update logistic_regressor_test.py

Replaced deprecated contrib with tf.losses.sigmoid_cross_entropy()

* Update logistic_regressor_test.py

Correcting losses function call

* Update losses_ops.py

Replace deprecated contrib with tf.losses

* Update wide.md

Minor explanation of abbreviate attribute

* Update logistic_regressor_test

Keeping all the headers the same

* Remove https from license

* Update ISSUE_TEMPLATE.md

Revert unrelated changes

* Revert README.md

Revert unrelated changes

* Revert wide.md

Revert unrelated changes

* Update wide.md

Reverting more changes