chore(*): OpenTrons -> Opentrons; v3a -> edge

[IanLondon]

#1701 reminded me that some OpenTrons not Opentrons lines still exist -- they're mostly in the outdated API docs, but I fixed the ones in PD.

Also tossed in changing the last remaining v3a to edge in PULL_REQUEST_TEMPLATE.

@mcous is it OK to edit PD's CHANGELOG like this? Or should I leave CHANGELOG and just change package.json, and it will correct it when it builds the next CHANGELOG?

[mcous]

🏗

Almost certain this changelog edit will persist. Pretty sure lerna/conventional-changelog only appends, not regenerates

[codecov]

Codecov Report

Merging #1704 into edge will decrease coverage by 1.09%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             edge    #1704     +/-   ##
=========================================
- Coverage   34.91%   33.81%   -1.1%     
=========================================
  Files         339      343      +4     
  Lines        5553     5754    +201     
=========================================
+ Hits         1939     1946      +7     
- Misses       3614     3808    +194

Impacted Files	Coverage Δ
protocol-designer/src/file-data/reducers/index.js	37.5% <0%> (-2.5%)	⬇️
protocol-designer/src/containers/Alerts.js	0% <0%> (ø)	⬆️
...rotocol-designer/src/containers/LabwareDropdown.js	0% <0%> (ø)	⬆️
protocol-designer/src/navigation/reducers/index.js	0% <0%> (ø)	⬆️
app/src/components/JogControls/index.js	0% <0%> (ø)	⬆️
...rotocol-designer/src/components/IngredientsList.js	0% <0%> (ø)	⬆️
...col-designer/src/containers/LabwareNameEditForm.js	0% <0%> (ø)	⬆️
app/src/components/ChangePipette/index.js	0% <0%> (ø)	⬆️
protocol-designer/src/svg/CopyIcon.js	0% <0%> (ø)	⬆️
app/src/pages/Robots.js	0% <0%> (ø)	⬆️
... and 89 more

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