chore: move all source files to new folder

Update the project structure to move all golang files to a new `src/`
folder. This keeps all the code located in the same place and easier to
work with.
Update the Makefile and goreleaser config to continue to work with the new
folder structure.

.goreleaser.yml

@@ -2,12 +2,11 @@
 # Make sure to check the documentation at http://goreleaser.com
 before:
   hooks:
-    # You may remove this if you don't use go modules.
-    - go mod download
-    # you may remove this if you don't need go generate
-    - go generate ./...
+    - make install-deps
 builds:
-  - goos:
+  -
+    dir: src
+    goos:
       - linux
       - windows
       - darwin

Makefile

@@ -1,18 +1,18 @@
 install-deps:
-	go mod download
+	cd src/ && go mod download
 
 # Standard go test
 test:
-	go test ./... -v -race
+	cd src/ && go test ./... -v -race
 
 # Make sure no unnecessary dependencies are present
 go-mod-tidy:
-	go mod tidy -v
+	cd src/ && go mod tidy -v
 	git diff-index --quiet HEAD
 
 format:
-	go fmt $(go list ./... | grep -v /vendor/)
-	go vet $(go list ./... | grep -v /vendor/)
+	cd src/ && go fmt $(go list ./... | grep -v /vendor/)
+	cd src/ && go vet $(go list ./... | grep -v /vendor/)
 
 generateChangelog:
 	./tools/git-chglog_linux_amd64 --config tools/chglog/config.yml 0.0.0.. > CHANGELOG.md