Upgrade Go version and dependencies

Bumping versions

Go version

To 1.19, to be consistent across all ST repos. Sometime post-releases we should bump all repos to 1.21.

golang.org/x/crypto

This is what changed in x/crypto from v0.19.0 to v0.22.0:

d042a39 (tag: v0.22.0) go.mod: update golang.org/x dependencies
b92bf94 ssh: respect MaxAuthTries also for "none" auth attempts
6f79b5a ssh: add server side multi-step authentication
8d0d405 x/crypto/chacha20: cleanup chacha_ppc64le.s
b91329d all: remove redundant words in comments and fix some typos
7067223 (tag: v0.21.0) go.mod: update golang.org/x dependencies
0d2316b ssh/test: work around for TestCiphers failures on macOS
0aab8d0 (tag: v0.20.0) all: update go.mod x/net dependency
5bead59 ocsp: don't use iota for externally defined constants
1a86580 x/crypto/internal/poly1305: improve sum_ppc64le.s
1c981e6 ssh/test: don't use DSA keys in integrations tests, update test RSA key
62c9f17 x509roots/nss: manually exclude a confusingly constrained root
405cb3b (tag: v0.19.0) go.mod: update golang.org/x dependencies

It's dependencies are:

module golang.org/x/crypto

go 1.18

require (
        golang.org/x/net v0.21.0 // tagx:ignore
        golang.org/x/sys v0.19.0
        golang.org/x/term v0.19.0
)

require golang.org/x/text v0.14.0 // indirect

I haven't recursively looked at this, but seems reasonable to just bump this and follow upstream.

stboot

From v0.3.5 (pre-release) to v0.3.6 (release), didn't do any due diligence for this one.

Remark

Keeping the same u-root version as stboot. No other direct dependencies have updates (I enumerated them one by one with go list -m -u example.com/MODULE to see what had upgrades).

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Part of #35 (closed).