docs: Replace `go get` with `go install` for command installation (#9098)

`go get` is deprecated for installation of commands as of go v1.17
Ref: https://go.googlesource.com/go/+/ced0fdbad0655d63d535390b1a7126fd1fef8348

Signed-off-by: Frederic Hemberger <mail@frederic-hemberger.de>

README.md

@@ -63,10 +63,10 @@ installed in order to build the frontend assets.
 You can directly use the `go` tool to download and install the `prometheus`
 and `promtool` binaries into your `GOPATH`:
 
-    $ GO111MODULE=on go get github.com/prometheus/prometheus/cmd/...
+    $ GO111MODULE=on go install github.com/prometheus/prometheus/cmd/...
     $ prometheus --config.file=your_config.yml
 
-*However*, when using `go get` to build Prometheus, Prometheus will expect to be able to
+*However*, when using `go install` to build Prometheus, Prometheus will expect to be able to
 read its web assets from local filesystem directories under `web/ui/static` and
 `web/ui/templates`. In order for these assets to be found, you will have to run Prometheus
 from the root of the cloned repository. Note also that these directories do not include the

documentation/prometheus-mixin/README.md

@@ -9,9 +9,9 @@ and dashboards for Prometheus.
 To use them, you need to have `jsonnet` (v0.13+) and `jb` installed. If you
 have a working Go development environment, it's easiest to run the following:
 ```bash
-$ go get github.com/google/go-jsonnet/cmd/jsonnet
-$ go get github.com/google/go-jsonnet/cmd/jsonnetfmt 
-$ go get github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb
+$ go install github.com/google/go-jsonnet/cmd/jsonnet@latest
+$ go install github.com/google/go-jsonnet/cmd/jsonnetfmt@latest
+$ go install github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb@latest
 ```
 
 _Note: The make targets `lint` and `fmt` need the `jsonnetfmt` binary, which is

scripts/genproto.sh

@@ -15,7 +15,7 @@ if ! [[ $(protoc --version) =~ "3.15.8" ]]; then
 	exit 255
 fi
 
-# Since we run go get, go mod download, the go.sum will change.
+# Since we run go install, go mod download, the go.sum will change.
 # Make a backup.
 cp go.sum go.sum.bak