build: upgrade Go and Docker toolchains to 1.27.1

Dockerfile

@@ -1,5 +1,5 @@
 # Dockerfile for gotify production
-FROM golang:alpine3.21 AS buildStage
+FROM golang:1.27.1-alpine AS buildStage
 LABEL maintainer="digIT <digit@chalmers.it>"
 
 # Install git

README.md

@@ -103,14 +103,14 @@ Run just these tests with `go test -race ./google_mail -run TestGmailIntegration
 They test our API integration contract, not Google-side permissions or delivery.
 
 ### Manual
-Make sure you have golang installed and you `$GOPATH` setup.
+Use Go 1.27.1, matching `go.mod`, CI, and the Docker build images.
 1. Follow the steps in [Setup](#setup) and enable debug mode.
 2. Grab all dependencies by standing in the project root and run `go get -d ./...`
 3. You find the main file in `cmd/main.go`
 4. Go to http://localhost:8080
 
 Use gin for hot reloading.
-1. Grab it with `go get github.com/codegangsta/gin`
+1. Grab it with `go install github.com/codegangsta/gin@v0.0.0-20230218063734-2c98d96c9244`
 2. Run gotify with `gin -d cmd -a 8080 run main.go`
 3. Go to http://localhost:3000
 

dev.Dockerfile

@@ -1,5 +1,5 @@
 # Dockerfile for gotify development
-FROM golang:alpine
+FROM golang:1.27.1-alpine
 MAINTAINER digIT <digit@chalmers.it>
 
 # Install git
@@ -8,7 +8,7 @@ RUN apk upgrade
 RUN apk add --update git
 
 RUN mkdir -p $GOPATH/bin && \
-    go get github.com/codegangsta/gin
+    go install github.com/codegangsta/gin@v0.0.0-20230218063734-2c98d96c9244
 
 # Add standard certificates
 RUN apk add ca-certificates && rm -rf /var/cache/apk/*
@@ -17,4 +17,4 @@ RUN apk add ca-certificates && rm -rf /var/cache/apk/*
 RUN mkdir -p /go/src/github.com/cthit/gotify
 WORKDIR $GOPATH/src/github.com/cthit/gotify
 
-CMD go get -d -v ./... && gin -d cmd -a 8080 run main.go
+CMD go mod download && gin -d cmd -a 8080 run main.go

go.mod

@@ -1,8 +1,6 @@
 module github.com/cthit/gotify
 
-go 1.23.0
-
-toolchain go1.23.7
+go 1.27.1
 
 require (
 	github.com/gocraft/web v0.0.0-20190207150652-9707327fb69b