Upgrade version + few improvements

[camilamacedo86]

Motivation

• Bump memcached sample operator to operator-sdk v0.10.0 #68
• Error "Error: failed to build test binary: (failed to exec []string{"go", "test", "./test/e2e//..." is faced when the impl is exactly equals the example operator-sdk#1830

required for the following as well:

• CSV keeps pending due to "CSV missing minimum kube version specification" getting-started#43
• CSV resources status was not updated after creating some required resources getting-started#44

What

• Upgrade go example from 0.6 to operator-sdk version: v0.10.0, commit: ff80b17737a6a0aade663e4827e8af3ab5a21170
• Add makefile in order to be easier to test the example and clarifies how to use it
• Add the new version of olm-catalogue files
• Change the Readme

Steps to verify

• Build an image with operator-sdk build
• Run make install and check that the Memcached pods are deployed and running

Following the local tests performed with the image cmacedo/memcached-operator:operator-sdk-samples

[jmrodri]

minor changes to the README. The rest looks okay to me.

[jmrodri]

Makefile looks good.

[theishshah]

The operator looks good, fan of the new Makefile! Agree with Jesus about the small comments on the Read Me

[camilamacedo86]

Hi @theishshah and @jmrodri,

Really tks for your review. All suggestions are applied.
Please, feel free to check and let me know if we can merge it.

Cheers,

[jmrodri]

/lgtm