Upgrade prometheus/procfs dependency, use Go1.21 (#296)

* Upgrade prometheus/procfs dependency and therefore set Go1.21 in go.mod

* Fix broken compatibility with prometheus/procfs

* Update README for Go1.21

---------

Co-authored-by: Thomas Delbende <thomas.delbende@bleemeo.com>

README.md

@@ -372,7 +372,7 @@ An example Grafana dashboard to view the metrics is available at https://grafana
 
 ## Building
 
-Requires Go 1.13 installed.
+Requires Go 1.21 (at least) installed.
 ```
 make
 ```
@@ -415,4 +415,4 @@ process_max_fds 1.048576e+06
 process_open_fds 10
 ```
 
-For further information about TLS configuration, please visit: [exporter-toolkit](https://github.com/prometheus/exporter-toolkit/blob/master/docs/web-configuration.md)
+For further information about TLS configuration, please visit: [exporter-toolkit](https://github.com/prometheus/exporter-toolkit/blob/master/docs/web-configuration.md)

go.mod

@@ -1,6 +1,6 @@
 module github.com/ncabatoff/process-exporter
 
-go 1.13
+go 1.21
 
 require (
 	github.com/google/go-cmp v0.6.0
@@ -9,7 +9,31 @@ require (
 	github.com/prometheus/client_golang v1.19.0
 	github.com/prometheus/common v0.52.3
 	github.com/prometheus/exporter-toolkit v0.11.0
-	github.com/prometheus/procfs v0.13.0
+	github.com/prometheus/procfs v0.14.0
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c
 	gopkg.in/yaml.v2 v2.4.0
 )
+
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/coreos/go-systemd/v22 v22.5.0 // indirect
+	github.com/go-kit/log v0.2.1 // indirect
+	github.com/go-logfmt/logfmt v0.5.1 // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/jpillora/backoff v1.0.0 // indirect
+	github.com/kr/pretty v0.3.1 // indirect
+	github.com/kr/text v0.2.0 // indirect
+	github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f // indirect
+	github.com/prometheus/client_model v0.6.0 // indirect
+	github.com/rogpeppe/go-internal v1.10.0 // indirect
+	github.com/stretchr/testify v1.9.0 // indirect
+	golang.org/x/crypto v0.21.0 // indirect
+	golang.org/x/net v0.22.0 // indirect
+	golang.org/x/oauth2 v0.18.0 // indirect
+	golang.org/x/sync v0.7.0 // indirect
+	golang.org/x/sys v0.19.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
+	google.golang.org/appengine v1.6.7 // indirect
+	google.golang.org/protobuf v1.33.0 // indirect
+)