Document changes to docker base images. Related to https://github.com/jreleaser/jreleaser/issues/133

docs/modules/configuration/pages/name-templates.adoc

@@ -79,10 +79,17 @@ The following names are related to the current build
 
 [%header, cols="<2,<5", width="100%"]
 |===
-| Key             | Description
-| commitShortHash | head commit hash abbreviated to 7 characters
-| commitFullHash  | head commit hash
-| timestamp       | current timestamp with RFC3339 format
+| Key                 | Description
+| commitShortHash     | head commit hash abbreviated to 7 characters
+| commitFullHash      | head commit hash
+| timestamp           | current timestamp with RFC3339 format
+| outputDirectory     | JReleaser's output directory
+| checksumDirectory   | directory where checksums are found
+| signaturesDirectory | directory where signatures are found
+| assembleDirectory   | directory where assembled distributions are found
+| artifactsDirectory  | directory where transformed artifacts are found
+| prepareDirectory    | base directory for preparing distributions
+| packageDirectory    | base directory for packaging distributions
 |===
 
 == Project

docs/modules/configuration/pages/packagers/docker.adoc

@@ -36,7 +36,7 @@ packagers:
 
     # The base Docker image to use.
     # icon:dot-circle[] icon:file-alt[]
-    baseImage: "alpine:3.5"
+    baseImage: "alpine:3.13.5"
 
     # A list of image names.
     # If unspecified, a single image `{{repoOwner}}/{{distributionName}}:{{tagName}}`
@@ -125,7 +125,7 @@ TOML::
 
   # The base Docker image to use.
   # icon:dot-circle[] icon:file-alt[]
-  baseImage = "alpine:3.5"
+  baseImage = "alpine:3.13.5"
 
   # A list of image names.
   # If unspecified, a single image `{{repoOwner}}/{{distributionName}}:{{tagName}}`
@@ -212,7 +212,7 @@ JSON::
 
       // The base Docker image to use.
       // icon:dot-circle[] icon:file-alt[]
-      "baseImage": "alpine:3.5",
+      "baseImage": "alpine:3.13.5",
 
       // A list of image names.
       // If unspecified, a single image `{{repoOwner}}/{{distributionName}}:{{tagName}}`
@@ -326,7 +326,7 @@ Maven::
         The base Docker image to use.
         icon:dot-circle[] icon:file-alt[]
       -->
-      <baseImage>alpine:3.5</baseImage>
+      <baseImage>alpine:3.13.5</baseImage>
 
       <!--
         A list of image names.
@@ -455,7 +455,7 @@ jreleaser {
 
       // The base Docker image to use.
       // icon:dot-circle[] icon:file-alt[]
-      baseImage = 'alpine:3.5'
+      baseImage = 'alpine:3.13.5'
 
       // A list of image names.
       // If unspecified, a single image `{{repoOwner}}/{{distributionName}}:{{tagName}}`
@@ -552,6 +552,14 @@ ENV PATH="${PATH}:/app-1.2.3/bin"
 ENTRYPOINT ["/app-1.2.3/bin/app"]
 ----
 
+== Base Images
+
+Different values for the default base image will be used depending on the distribution type:
+
+ * `azul/zulu-openjdk-alpine:${distribution.java.version}-jre` for JAVA_BINARY and SINGLE_JAR distributions.
+ * `alpine:3.13.5` for JLINK distributions.
+ * `scratch` for NATIVE_IMAGE distributions.
+
 == Default Labels
 
 JReleaser will add the following labels if they are not explicitly defined: