Remove `*` from `Cargo.toml` in http://examples.near.org/

[MaksymZavershynskyi]

Notation like this https://github.com/near-examples/rust-counter/blob/master/contract/Cargo.toml#L12-L13 gives no guarantee on what package is going to be fetched. I just tried compiling rust-counter on a fresh new macbook pro and it did not compile because of the version conflict between borsh and near-sdk-rs.

[willemneal]

Also those deps are provided by near_sdk now.

[austinabell]

Specific version is provided as well as a lockfile now