Refactor .goreleaser.yaml for improved release management and update README with installation instructions

Add script to append release notes and enhance publish-apt.sh for asset downloading

Signed-off-by: Marc Schäfer <git@marcschaeferger.de>

.goreleaser.yaml

@@ -1,42 +1,33 @@
+version: 2
 project_name: newt
 
 release:
-  # du nutzt Tags wie 1.2.3 und 1.2.3-rc.1 (ohne v)
   draft: true
-  prerelease: auto
+  prerelease: "{{ contains .Tag \"-rc.\" }}"
   name_template: "{{ .Tag }}"
-  mode: replace
 
 builds:
   - id: newt
-    main: ./main.go   # <- falls du cmd/newt hast: ./cmd/newt
+    main: ./main.go
     binary: newt
     env:
       - CGO_ENABLED=0
     goos:
       - linux
-      - darwin
-      - windows
-      - freebsd
     goarch:
       - amd64
       - arm64
-    goarm:
-      - "6"
-      - "7"
     flags:
       - -trimpath
     ldflags:
-      - -s -w -X main.version={{ .Tag }}
+      - -s -w -X main.newtVersion={{ .Tag }}
 
 archives:
-  # Wichtig: format "binary" -> keine tar.gz, sondern raw binary wie bei dir aktuell
-  - id: raw
+  - id: binaries
     builds:
       - newt
     format: binary
-    name_template: >-
-      {{ .ProjectName }}_{{ .Os }}_{{ if eq .Arch "amd64" }}amd64{{ else if eq .Arch "arm64" }}arm64{{ else if eq .Arch "386" }}386{{ else }}{{ .Arch }}{{ end }}{{ if .Arm }}v{{ .Arm }}{{ end }}{{ if .Mips }}_{{ .Mips }}{{ end }}{{ if .Amd64 }}_{{ .Amd64 }}{{ end }}{{ if .Riscv64 }}_{{ .Riscv64 }}{{ end }}{{ if .Os | eq "windows" }}.exe{{ end }}
+    name_template: "{{ .ProjectName }}_{{ .Os }}_{{ .Arch }}"
 
 checksum:
   name_template: "checksums.txt"
@@ -49,14 +40,13 @@ nfpms:
     vendor: fosrl
     maintainer: fosrl <repo@fosrl.io>
     description: Newt - userspace tunnel client and TCP/UDP proxy
-    license: AGPL-3.0
+    license: AGPL-3.0-or-later
     formats:
       - deb
       - rpm
       - apk
     bindir: /usr/bin
-    # sorgt dafür, dass die Paketnamen gut pattern-matchbar sind
-    file_name_template: "{{ .PackageName }}_{{ .Version }}_{{ .Arch }}"
+    file_name_template: "newt_{{ .Version }}_{{ .Arch }}"
     contents:
       - src: LICENSE
         dst: /usr/share/doc/newt/LICENSE