chore: convert true to always pull policy

[jbrockopp]

This PR updates the existing docs for the pull attribute to match the newly created pull policies.

To accomplish this, I performed a find and replace for converting

pull: true

to

pull: always

Also found in this PR is updating the tag for the Docker image we reference to latest 👍

[codecov]

Codecov Report

Merging #48 into master will decrease coverage by 2.79%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #48      +/-   ##
==========================================
- Coverage   49.14%   46.35%   -2.80%     
==========================================
  Files           9        9              
  Lines         409      384      -25     
==========================================
- Hits          201      178      -23     
+ Misses        206      204       -2     
  Partials        2        2              

Impacted Files	Coverage Δ
cmd/vela-kubernetes/plugin.go	58.13% <0.00%> (-1.87%)	⬇️
cmd/vela-kubernetes/kubectl.go	84.21% <0.00%> (-0.79%)	⬇️
cmd/vela-kubernetes/apply.go	96.15% <0.00%> (-0.52%)	⬇️
cmd/vela-kubernetes/status.go	96.29% <0.00%> (-0.48%)	⬇️
cmd/vela-kubernetes/patch.go	97.61% <0.00%> (-0.35%)	⬇️
cmd/vela-kubernetes/main.go	0.00% <0.00%> (ø)
cmd/vela-kubernetes/config.go	100.00% <0.00%> (ø)
cmd/vela-kubernetes/command.go	100.00% <0.00%> (ø)
cmd/vela-kubernetes/container.go	100.00% <0.00%> (ø)

[kneal]

LGTM 🐬

[KellyMerrick]

lgtm