TUN-10557: Bump quic-go v0.59.1

Bumps quic-go to v0.59.1 (chungthuang fork rebased from upstream v0.45 onto
v0.59.1). Upstream removed the `logging` package and replaced its
callback-based ConnectionTracer with the structured `qlog`/`qlogwriter` event
API, which required migrating cloudflared's QUIC metrics collection.

Migrations:

- quic/tracing.go: connTracer no longer fills a logging.ConnectionTracer
  callback struct. It implements qlogwriter.Trace + qlogwriter.Recorder and
  dispatches qlog events (PacketSent, PacketReceived, MetricsUpdated, ...) to
  the collector through RecordEvent. NewClientTracer now returns a function
  compatible with quic.Config.Tracer.

- quic/metrics.go: collector methods take qlog types (qlog.Frame,
  qlog.PacketType, qlog.MetricsUpdated, ...) and plain int64 in place of the
  removed logging.ByteCount/Frame/RTTStats/TransportParameters.

- quic/conversion.go: PacketType, PacketDropReason and PacketLossReason are
  strings upstream rather than numeric iotas, so the converters become
  pass-through allowlists. CongestionState is also a string;
  congestionStateToFloat maps it back to the numeric gauge values cloudflared
  exports.

- quic.Connection/quic.Stream became *quic.Conn/*quic.Stream; updated
  ConnWithCloser, SafeStreamCloser and the connection package accordingly.
  Tests and generated mocks (mocks/mock_quic_connection.go) were adapted to
  the new pointer-based API.

Closes TUN-10557

vendor/github.com/go-task/slim-sprig/v3/README.md

@@ -1,73 +0,0 @@
-# Slim-Sprig: Template functions for Go templates [![Go Reference](https://pkg.go.dev/badge/github.com/go-task/slim-sprig/v3.svg)](https://pkg.go.dev/github.com/go-task/slim-sprig/v3)
-
-Slim-Sprig is a fork of [Sprig](https://github.com/Masterminds/sprig), but with
-all functions that depend on external (non standard library) or crypto packages
-removed.
-The reason for this is to make this library more lightweight. Most of these
-functions (specially crypto ones) are not needed on most apps, but costs a lot
-in terms of binary size and compilation time.
-
-## Usage
-
-**Template developers**: Please use Slim-Sprig's [function documentation](https://go-task.github.io/slim-sprig/) for
-detailed instructions and code snippets for the >100 template functions available.
-
-**Go developers**: If you'd like to include Slim-Sprig as a library in your program,
-our API documentation is available [at GoDoc.org](http://godoc.org/github.com/go-task/slim-sprig).
-
-For standard usage, read on.
-
-### Load the Slim-Sprig library
-
-To load the Slim-Sprig `FuncMap`:
-
-```go
-
-import (
-  "html/template"
-
-  "github.com/go-task/slim-sprig"
-)
-
-// This example illustrates that the FuncMap *must* be set before the
-// templates themselves are loaded.
-tpl := template.Must(
-  template.New("base").Funcs(sprig.FuncMap()).ParseGlob("*.html")
-)
-```
-
-### Calling the functions inside of templates
-
-By convention, all functions are lowercase. This seems to follow the Go
-idiom for template functions (as opposed to template methods, which are
-TitleCase). For example, this:
-
-```
-{{ "hello!" | upper | repeat 5 }}
-```
-
-produces this:
-
-```
-HELLO!HELLO!HELLO!HELLO!HELLO!
-```
-
-## Principles Driving Our Function Selection
-
-We followed these principles to decide which functions to add and how to implement them:
-
-- Use template functions to build layout. The following
-  types of operations are within the domain of template functions:
-  - Formatting
-  - Layout
-  - Simple type conversions
-  - Utilities that assist in handling common formatting and layout needs (e.g. arithmetic)
-- Template functions should not return errors unless there is no way to print
-  a sensible value. For example, converting a string to an integer should not
-  produce an error if conversion fails. Instead, it should display a default
-  value.
-- Simple math is necessary for grid layouts, pagers, and so on. Complex math
-  (anything other than arithmetic) should be done outside of templates.
-- Template functions only deal with the data passed into them. They never retrieve
-  data from a source.
-- Finally, do not override core Go template functions.