Add linter actions

.github/workflows/go.yml

@@ -22,11 +22,8 @@ jobs:
               dep ensure
           fi
 
-      - name: Install golangci-lint
-        run: curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.22.2
-
-      - name: Lint
-        run: /home/runner/go/bin/golangci-lint run
+      - name: GolangCI-Lint
+        uses: Mushus/golangci-linter@v1.1.2
 
       - name: Test
         run: go test -v .

README.md

@@ -3,6 +3,10 @@
 
 Goxirr is a simple implementation of a function for calculating the Internal Rate of Return for irregular cash flow (XIRR).
 
+## Links
+- [Wikipedia](https://en.wikipedia.org/wiki/Internal_rate_of_return)
+- [Excel support](https://support.office.com/en-us/article/XIRR-function-DE1242EC-6477-445B-B11B-A303AD9ADC9D)
+
 ## Example
 
 ```go

xirr.go

@@ -9,16 +9,16 @@ import (
 	"time"
 )
 
-//A Transaction represents a single transaction from a series of irregular payments.
+//A Transaction represent a single transaction from a series of irregular payments.
 type Transaction struct {
 	Date time.Time
 	Cash float64
 }
 
-//Transactions represents a cash flow consisting of individual transactions
+//Transactions represent a cash flow consisting of individual transactions
 type Transactions []Transaction
 
-//Xirr return the Internal Rate of Return (IRR) for an irregular series of cash flows (XIRR)
+//Xirr returns the Internal Rate of Return (IRR) for an irregular series of cash flows (XIRR)
 func Xirr(transactions Transactions) float64 {
 	var years []float64
 	for _, t := range transactions {