Clarify maintainer responsibilities

[fredjn]

Applicable Issues

#141

Description of the Change

Added information about the maintainer responsibilities with emphasis on details regarding security and vulnerabilities

Alternate Designs

N/A

Benefits

Easier for new (and old?) maintainers to understand their responsibilities

Possible Drawbacks

None that I can see

Sign-off

Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
have the right to submit it under the open source license
indicated in the file; or

(b) The contribution is based upon previous work that, to the best
of my knowledge, is covered under an appropriate open source
license and I have the right under that license to submit that
work with modifications, whether created in whole or in part
by me, under the same open source license (unless I am
permitted to submit under a different license), as indicated
in the file; or

(c) The contribution was provided directly to me by some other
person who certified (a), (b) or (c) and I have not modified
it.

(d) I understand and agree that this project and the contribution
are public and that a record of the contribution (including all
personal information I submit with it, including my sign-off) is
maintained indefinitely and may be redistributed consistent with
this project or the open source license(s) involved.

Signed-off-by: Fredrik Fristedt <[email protected]>

[magnusbaeck]

Could be amended slightly to include #153.