refactor: use git command instead of go-git

The current implementation of go-git has a high memory cost. Since our
needs are not that complex, we can use the default git CLI.

Reference:
go-git/go-git#315

Dockerfile

@@ -9,12 +9,12 @@ COPY . .
 
 RUN CGO_ENABLED=0 GOOS=linux go build -o /zettelkasten-exporter
 
-FROM gcr.io/distroless/base-debian12 AS release-stage
+FROM alpine:3 AS release-stage
 
 WORKDIR /
 
 COPY --from=build-stage /zettelkasten-exporter /zettelkasten-exporter
 
-USER nonroot:nonroot
+RUN apk add git
 
 ENTRYPOINT ["/zettelkasten-exporter"]

go.mod

@@ -3,7 +3,6 @@ module github.com/luissimas/zettelkasten-exporter
 go 1.22.2
 
 require (
-	github.com/go-git/go-git/v5 v5.12.0
 	github.com/gookit/validate v1.5.2
 	github.com/influxdata/influxdb-client-go/v2 v2.13.0
 	github.com/knadh/koanf v1.5.0
@@ -13,40 +12,23 @@ require (
 )
 
 require (
-	dario.cat/mergo v1.0.0 // indirect
-	github.com/Microsoft/go-winio v0.6.1 // indirect
-	github.com/ProtonMail/go-crypto v1.0.0 // indirect
 	github.com/apapsch/go-jsonmerge/v2 v2.0.0 // indirect
-	github.com/cloudflare/circl v1.3.7 // indirect
-	github.com/cyphar/filepath-securejoin v0.2.4 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	github.com/emirpasic/gods v1.18.1 // indirect
 	github.com/fatih/structs v1.1.0 // indirect
 	github.com/fsnotify/fsnotify v1.7.0 // indirect
-	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
-	github.com/go-git/go-billy/v5 v5.5.0 // indirect
-	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/google/uuid v1.3.1 // indirect
 	github.com/gookit/filter v1.2.1 // indirect
 	github.com/gookit/goutil v0.6.15 // indirect
 	github.com/influxdata/line-protocol v0.0.0-20200327222509-2487e7298839 // indirect
-	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
-	github.com/kevinburke/ssh_config v1.2.0 // indirect
+	github.com/kr/pretty v0.3.1 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	github.com/oapi-codegen/runtime v1.0.0 // indirect
-	github.com/pjbgf/sha1cd v0.3.0 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
-	github.com/sergi/go-diff v1.3.2-0.20230802210424-5b0b94c5c0d3 // indirect
-	github.com/skeema/knownhosts v1.2.2 // indirect
-	github.com/xanzy/ssh-agent v0.3.3 // indirect
-	golang.org/x/crypto v0.21.0 // indirect
-	golang.org/x/mod v0.12.0 // indirect
+	github.com/rogpeppe/go-internal v1.11.0 // indirect
 	golang.org/x/net v0.23.0 // indirect
-	golang.org/x/sys v0.18.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
-	golang.org/x/tools v0.13.0 // indirect
-	gopkg.in/warnings.v0 v0.1.2 // indirect
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )