Correct way to add GPG key (#2459)

using /etc/apt/keyrings is deprecated, see https://manpages.debian.org/testing/apt/apt-key.8.en.html

content/asciidoc-pages/installation/linux/index.adoc

@@ -43,15 +43,14 @@ apt install -y wget apt-transport-https
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 [source, bash]
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-mkdir -p /etc/apt/keyrings
-wget -O - https://packages.adoptium.net/artifactory/api/gpg/key/public | tee /etc/apt/keyrings/adoptium.asc
+wget -qO - https://packages.adoptium.net/artifactory/api/gpg/key/public | gpg --dearmor | tee /etc/apt/trusted.gpg.d/adoptium.gpg > /dev/null
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 +
 . Configure the Eclipse Adoptium apt repository. To check the full list of versions supported take a look at the list in the tree at https://packages.adoptium.net/ui/native/deb/dists/.
 +
 [source, bash]
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-echo "deb [signed-by=/etc/apt/keyrings/adoptium.asc] https://packages.adoptium.net/artifactory/deb $(awk -F= '/^VERSION_CODENAME/{print$2}' /etc/os-release) main" | tee /etc/apt/sources.list.d/adoptium.list
+echo "deb https://packages.adoptium.net/artifactory/deb $(awk -F= '/^VERSION_CODENAME/{print$2}' /etc/os-release) main" | tee /etc/apt/sources.list.d/adoptium.list
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 TIP: For Linux Mint (based on Ubuntu) you have to replace `VERSION_CODENAME` with `UBUNTU_CODENAME`.
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