Change interface to slice of pin from slice of pointer to interface (#45

)

Update dependencies

Ran:
  go get -u -t ./...
  go mod tidy

Update minimum go to 1.17

Update dependency.
Update github actions too.
Ran gofmt.
Get rid of io/ioutil.

Add PulseIn function (#18)

Use clockwork.FakeClock in WaitForEdge_Noise_* (#16)

This reduces testing time by:

* 2 seconds per WaitForEdge_Noise_Edge run
* 1 second per WaitForEdge_Noise_Got run

No further tests in debounce_test.go sleep.

Add gohci forward tests

Test with host, devices and cmd with the current conn commit.

README.md: add slack link

People looking at v0 are probably in need of help.

Add the slack reference here to increase the chance of them on-boarding
properly with the guidance to try v3. I removed it by accident in the
previous change.

Create a new v1 version to clear ambiguity

As I had feared, people use the non-v3, thus getting the old code and
then start copying examples using v3 and they get super confused! Remove
all the code in v1 so people at least get clear failure instead of
incomprehensible errors.

v3: migrate to v3

The goal is two parts:
- since this code is the same as periph v3.6, make it the same version
  as periph.io/x/periph version, otherwise we'd have "periph.io/x/conn
  v1 is equivalent to periph.io/x/periph v3" which is confusing.
- go modules refuses v0 and v1 in the go module path, and starting with
  v3 makes all the imports use a version number right away. It has two
  purposes:
  - it helps disambiguate quickly when looking at imports to see if the
    old periph.io/x/periph path is used or the new ones.
  - since it's versioned already, it'll make bumping to v4 and later
    easier to search-and-replace.