feat: checksums.split (#4707)

closes #4618
closes #4641

---------

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

www/docs/customization/checksum.md

@@ -10,7 +10,8 @@ The `checksum` section allows customizations of the filename:
 checksum:
   # You can change the name of the checksums file.
   #
-  # Default: {{ .ProjectName }}_{{ .Version }}_checksums.txt
+  # Default: '{{ .ProjectName }}_{{ .Version }}_checksums.txt'
+  #   or, when split is set: '{{ .ArtifactName }}.{{ .Algorithm }}'
   # Templates: allowed
   name_template: "{{ .ProjectName }}_checksums.txt"
 
@@ -20,6 +21,10 @@ checksum:
   # Default: sha256.
   algorithm: sha256
 
+  # If true, will create one checksum file for each artifact.
+  # Since: v1.25
+  split: true
+
   # IDs of artifacts to include in the checksums file.
   #
   # If left empty, all published binaries, archives, linux packages and source archives

www/docs/customization/templates.md

@@ -133,9 +133,9 @@ In the nFPM name template field, you can use those extra fields:
 
 In the `release.body` field, you can use these extra fields:
 
-| Key          | Description                                                                         |
-| ------------ | ----------------------------------------------------------------------------------- |
-| `.Checksums` | the current checksum file contents. Only available in the release body. Since v1.19 |
+| Key          | Description                                                                                                                                            |
+| ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| `.Checksums` | the current checksum file contents, or a map of filename/checksum contents if `checksum.split` is set. Only available in the release body. Since v1.19 |
 
 ## Functions