[Feature request] Add cos-e v1.0
> @mariamabarham Just wanted to note that default behavior `cos_e = load_dataset("cos_e")` now loads `v1.0`. Not sure if this is intentional (but the flag specification does work as intended).

In the new version of `nlp`, if you try `cos_e = load_dataset("cos_e")` it throws this error:
```
ValueError: Config name is missing.
Please pick one among the available configs: ['v1.0', 'v1.11']
Example of usage:
	`load_dataset('cos_e', 'v1.0')`
```
For datasets with at least two configurations, we now force the user to pick one (no default)
I noticed the second release of cos-e (v1.11) is included in this repo. I wanted to request inclusion of v1.0, since this is the version on which results are reported on in [the paper](https://www.aclweb.org/anthology/P19-1487/), and v1.11 has noted [annotation](https://github.com/salesforce/cos-e/issues/2) [issues](https://arxiv.org/pdf/2004.14546.pdf).
[Feature request] Add cos-e v1.0 
 I noticed the second release of cos-e (v1.11) is included in this repo. I wanted to request inclusion of v1.0, since this is the version on which results are reported on in [the paper](https://www.aclweb.org/anthology/P19-1487/), and v1.11 has noted [annotation](https://github.com/salesforce/cos-e/issues/2) [issues](https://arxiv.org/pdf/2004.14546.pdf). 
 > @mariamabarham Just wanted to note that default behavior `cos_e = load_dataset("cos_e")` now loads `v1.0`. Not sure if this is intentional (but the flag specification does work as intended).

In the new version of `nlp`, if you try `cos_e = load_dataset("cos_e")` it throws this error:
```
ValueError: Config name is missing.
Please pick one among the available configs: ['v1.0', 'v1.11']
Example of usage:
	`load_dataset('cos_e', 'v1.0')`
```
For datasets with at least two configurations, we now force the user to pick one (no default)