Tap14 updates (#158)

* [TAP 14] Replace reference to TAP 5 with TAP 13

Signed-off-by: Marina Moore <marina@chainguard.dev>

* [TAP 14] Add supported-version file

Signed-off-by: Marina Moore <marina@chainguard.dev>

* [TAP 14] typos and clarifications from code review

Signed-off-by: Marina Moore <marina@chainguard.dev>

* [TAP 14] change directory names 2.0.0 -> 2

Signed-off-by: Marina Moore <marina@chainguard.dev>

* [TAP 14] minor changes from code review

Signed-off-by: Marina Moore <marina@chainguard.dev>

* clarify backwards compatibility and type of 'version'

Signed-off-by: Marina Moore <mnm678@gmail.com>

* [TAP 14] change fields in supported-versions.json

Signed-off-by: Marina Moore <mnm678@gmail.com>

* [TAP 14] supported-versions -> supported-versions.json

Signed-off-by: Marina Moore <mnm678@gmail.com>

* [TAP 14] updated format for supported-versions.json

Signed-off-by: Marina Moore <mnm678@gmail.com>

* Apply suggestions from code review

Co-authored-by: Trishank Karthik Kuppusamy <trishank.kuppusamy@datadoghq.com>
Signed-off-by: Marina Moore <mnm678@users.noreply.github.com>

* move supported versions into root metadata

Signed-off-by: Marina Moore <mnm678@gmail.com>

* TAP 14: Fix new field name inconsistency

Consistently use "supported_versions" (with underscore) as name
for newly added field.

Signed-off-by: Lukas Puehringer <lukas.puehringer@nyu.edu>

* TAP 14: Fix update metadata parsing order

In a real TUF client update timestamp parsing happens before
snapshot parsing.

Signed-off-by: Lukas Puehringer <lukas.puehringer@nyu.edu>

* TAP 14: Rm bad example of backwards compatible TAP

TAP 10 is wrongly used as example for a backwards compatible TAP,
at least according to the "Backwards Compatibility" section in
TAP 10:
https://github.com/theupdateframework/taps/blob/master/tap10.md#backwards-compatibility

Signed-off-by: Lukas Puehringer <lukas.puehringer@nyu.edu>

* TAP 14: Clarify "expires" vs. "becomes_obsolete"

Signed-off-by: Lukas Puehringer <lukas.puehringer@nyu.edu>

* TAP 14: Clarify how the name convention can change

Signed-off-by: Lukas Puehringer <lukas.puehringer@nyu.edu>

* Simplify root update for TAP 14

Signed-off-by: Marina Moore <mnm678@gmail.com>

Signed-off-by: Marina Moore <marina@chainguard.dev>
Signed-off-by: Marina Moore <mnm678@gmail.com>
Signed-off-by: Marina Moore <mnm678@users.noreply.github.com>
Signed-off-by: Lukas Puehringer <lukas.puehringer@nyu.edu>
Co-authored-by: Trishank Karthik Kuppusamy <trishank.kuppusamy@datadoghq.com>
Co-authored-by: Lukas Puehringer <lukas.puehringer@nyu.edu>

Author: 3 people